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Technical standards and commentaries for port and harbour facilties in japan

Technical standards and commentaries for port and harbour facilties in japan

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  • 1. The Overseas Coastal Area Development Institute of Japan3-2-4 Kasumigaseki, Chiyoda-ku, Tokyo, 100-0013, JapanCopyright © 2002 by The Overseas Coastal Area Development Institute of JapanPrinted by Daikousha Printing Co., Ltd.All rights reserved. No part of this publication may be reproduced, stored in a retrieval systems,transmitted in any form or by any means, electric, mechanical, photocopying, recording or otherwise,without the prior written permission of the publisher.Original Japanese language edition published by the Japan Ports and Harbours Association.Printed in Japan
  • 2. PREFACE-i-PrefaceThis book is a translation of the major portion of the Technical Standards and Commentaries of Portand Harbour Facilities in Japan (1999 edition) published by the Japan Port and Harbour Association,stipulated by the Ordinance of the Minister of Transport, which was issued in April 1999. The translationcovers about two thirds of the Japanese edition.Japanese islands have a long extension of coastline, measuring about 34,000 km, for the total land areaof some 380,000 square kilometers. Throughout her history, Japan has depended on the ports and harborson daily living and prosperity of people there. Japan did not develop extensive inland canal systems asfound in the European Continent because of its mountainous geography, but rather produced many harborsand havens along its coastline in the past. Today, the number of officially designated commercial ports andharbors amounts to about 1,100 and the number of fishing ports exceeds 3,000.After 220 years of isolation from the world civilization from the 17th to 19th centuries, Japan began tomodernize its society and civilization rapidly after the Meiji revolution in 1868. Modern technology of portand harbor engineering has been introduced by distinguished engineers from abroad and learned by manyambitious and capable young engineers in Japan. Ports of Yokohama, Kobe, and others began toaccommodate large ocean-going vessels in the late 19th century as the Japanese economy had shown arapid growth.Japanese engineers had drafted an engineering manual on design and construction of port and harborfacilities as early as in 1943. The manual was revised in 1959 with inclusion of new technology such asthose of coastal engineering and geotechnical engineering, which were developed during the SecondWorld War or just before it. The Japanese economy that was utterly destroyed by the war had begun torebuild itself rapidly after the 1950s. There were so many demands for the expansion of port and harborfacilities throughout Japan. Engineers were urged to design and construct facilities after facilities. Japanhas built the breakwaters and the quays with the rate of about 20,000 meters each per year throughout the1960s, 1970s, and 1980s.Such a feat of port development was made possible with provision of sound engineering manuals. TheMinistry of Land, Infrastructure and Transport (formerly the Ministry of Transport up to January 2001)which was responsible for port development and operation, revised the basic law on ports and harbors in1974 so as to take responsibility for provision of technical standards for design, construction, andmaintenance of port and harbor facilities. The first official technical standards and commentaries for portand harbor facilities were issued in 1979, and published by the Japan Port and Harbour Association forgeneral use. The technical standards were prepared by a technical committee composed of governmentengineers within the former Ministry of Transport, including members of the Port and Harbour ResearchInstitute and several District Port Construction Bureaus that were responsible for design and constructionin the field. Its English version was published by the Overseas Coastal Area Development Institute in1980, but it introduced only the skeleton of the Japanese version without giving the details.The Technical Standards and Commentaries for Port and Harbor Facilities in Japan have been revisedin 1988 and 1999, each time incorporating new technological developments. The present Englishtranslation endeavors to introduce the newest edition of 1999 to the port and harbor engineers overseas. Itis a direct translation of essential parts of Japanese edition. Many phrases and expressions reflect thecustomary, regulatory writings in Japanese, which are often awkward in English. Some sentences aftertranslation may not be fluent enough and give troubles for decipher. The editors in charge of translationrequest the readers for patience and generosity in their efforts for understanding Japanese technology inport and harbor engineering.With the globalization in every aspect of human activities, indigenous practices and customs are forcedto comply with the world standards. Technology by definition is supposed to be universal. Nevertheless,each country has developed its own specialty to suit its local conditions. The overseas readers may findsome of Japanese technical standards strange and difficult for adoption for their usage. Such conflicts intechnology are the starting points for mutual understanding and further developments in the future. Theeditors wish wholeheartedly this English version of Japanese technical standards be welcomed by theoverseas colleagues and serve for the advancement of port and harbor technology in the world.January 2002Y. Goda, T. Tabata and S. YamamotoEditors for translation version
  • 3. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-ii-
  • 4. CONTENTS-iii-CONTENTSPrefacePart I GeneralChapter 1 General Rules.................................................................................................................................................11.1 Scope of Application .............................................................................................................................11.2 Definitions ...............................................................................................................................................21.3 Usage of SI Units...................................................................................................................................2Chapter 2 Datum Level for Construction Work.........................................................................................................4Chapter 3 Maintenance....................................................................................................................................................5Part II Design ConditionsChapter 1 General .............................................................................................................................................................7Chapter 2 Vessels..............................................................................................................................................................92.1 Dimensions of Target Vessel...............................................................................................................92.2 External Forces Generated by Vessels ...........................................................................................162.2.1 General .....................................................................................................................................162.2.2 Berthing.....................................................................................................................................16[1] Berthing Energy..................................................................................................................16[2] Berthing Velocity ................................................................................................................17[3] Eccentricity Factor..............................................................................................................20[4] Virtual Mass Factor ............................................................................................................212.2.3 Moored Vessels .......................................................................................................................22[1] Motions of Moored Vessel..................................................................................................22[2] Waves Acting on Vessel.....................................................................................................22[3] Wind Load Acting on Vessel ..............................................................................................23[4] Current Forces Acting on Vessel........................................................................................24[5] Load-Deflection Characteristics of Mooring System ..........................................................252.2.4 Tractive Force Acting on Mooring Post and Bollard..................................................................25Chapter 3 Wind and Wind Pressure ..........................................................................................................................283.1 General..................................................................................................................................................283.2 Wind.......................................................................................................................................................293.3 Wind Pressure......................................................................................................................................30Chapter 4 Waves..............................................................................................................................................................324.1 General..................................................................................................................................................324.1.1 Procedure for Determining the Waves Used in Design.............................................................324.1.2 Waves to Be Used in Design ....................................................................................................324.1.3 Properties of Waves..................................................................................................................33[1] Fundamental Properties of Waves.....................................................................................33[2] Statistical Properties of Waves...........................................................................................37[3] Wave Spectrum..................................................................................................................384.2 Method of Determining Wave Conditions to Be Used in Design .................................................404.2.1 Principles for Determining the Deepwater Waves Used in Design ...........................................404.2.2 Procedure for Obtaining the Parameters of Design Waves ......................................................414.3 Wave Hindcasting................................................................................................................................424.3.1 General .....................................................................................................................................424.3.2 Wave Hindcasting in Generating Area......................................................................................424.3.3 Swell Hindcasting......................................................................................................................464.4 Statistical Processing of Wave Observation and Hindcasted Data.............................................474.5 Transformations of Waves .................................................................................................................494.5.1 General .....................................................................................................................................494.5.2 Wave Refraction........................................................................................................................494.5.3 Wave Diffraction........................................................................................................................52[1] Diffraction ...........................................................................................................................52[2] Combination of Diffraction and Refraction..........................................................................694.5.4 Wave Reflection........................................................................................................................70
  • 5. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-iv-[1] General .............................................................................................................................. 70[2] Reflection Coefficient......................................................................................................... 71[3] Transformation of Waves at Concave Corners, near the Heads of Breakwaters,and around Detached Breakwaters ................................................................................... 724.5.5 Wave Shoaling.......................................................................................................................... 744.5.6 Wave Breaking ......................................................................................................................... 754.6 Wave Runup, Overtopping, and Transmission............................................................................... 804.6.1 Wave Runup............................................................................................................................. 804.6.2 Wave Overtopping .................................................................................................................... 844.6.3 Wave Transmission .................................................................................................................. 904.7 Wave Setup and Surf Beat................................................................................................................ 914.7.1 Wave Setup .............................................................................................................................. 914.7.2 Surf Beat................................................................................................................................... 924.8 Long-Period Waves and Seiche ....................................................................................................... 934.9 Waves inside Harbors ........................................................................................................................ 944.9.1 Calmness and Disturbances..................................................................................................... 944.9.2 Evaluation of Harbor Calmness ................................................................................................ 944.10 Ship Waves .......................................................................................................................................... 94Chapter 5 Wave Force................................................................................................................................................. 1005.1 General ...............................................................................................................................................1005.2 Wave Force Acting on Upright Wall ...............................................................................................1005.2.1 General Considerations..........................................................................................................1005.2.2 Wave Forces of Standing and Breaking Waves .....................................................................101[1] Wave Force under Wave Crest........................................................................................101[2] Wave Force under Wave Trough..................................................................................... 1055.2.3 Impulsive Pressure Due to Breaking Waves ..........................................................................1065.2.4 Wave Force on Upright Wall Covered with Wave-Dissipating Concrete Blocks.....................1095.2.5 Effect of Alignment of Breakwater on Wave Force ................................................................. 1105.2.6 Effect of Abrupt Change in Water Depth on Wave Force ....................................................... 1105.2.7 Wave Force on Upright Wall near Shoreline or on Shore........................................................111[1] Wave Force at the Seaward Side of Shoreline .................................................................111[2] Wave Force at the Landward Side of Shoreline ...............................................................1115.2.8 Wave Force on Upright Wave-Absorbing Caisson ..................................................................1115.3 Mass of Armor Stones and Concrete Blocks................................................................................ 1125.3.1 Armor Units on Slope.............................................................................................................. 1125.3.2 Armor Units on Foundation Mound of Composite Breakwater ............................................... 1175.4 Wave Forces Acting on Cylindrical Members and Large Isolated Structures ......................... 1195.4.1 Wave Force on Cylindrical Members...................................................................................... 1195.4.2 Wave Force on Large Isolated Structure ................................................................................1215.5 Wave Force Acting on Structure Located near the Still Water Level........................................ 1225.5.1 Uplift Acting on Horizontal Plate near the Still Water Level ....................................................122Chapter 6 Tides and Abnormal Water Levels.......................................................................................................1276.1 Design Water Level...........................................................................................................................1276.2 Astronomical Tide .............................................................................................................................1286.3 Storm Surge.......................................................................................................................................1286.4 Tsunami ..............................................................................................................................................1306.5 Seiche ................................................................................................................................................. 1336.6 Groundwater Level and Permeation ..............................................................................................135Chapter 7 Currents and Current Force...................................................................................................................1387.1 General ...............................................................................................................................................1387.2 Current Forces Acting on Submerged Members and Structures ..............................................1387.3 Mass of Armor Stones and Concrete Blocks against Currents .................................................140Chapter 8 External Forces Acting on Floating Body and Its Motions ...........................................................1428.1 General ...............................................................................................................................................1428.2 External Forces Acting on Floating Body ......................................................................................1438.3 Motions of Floating Body and Mooring Force............................................................................... 145Chapter 9 Estuarine Hydraulics ................................................................................................................................1489.1 General ...............................................................................................................................................148Chapter 10 Littoral Drift ..................................................................................................................................................15410.1 General ...............................................................................................................................................15410.2 Scouring around Structures.............................................................................................................16110.3 Prediction of Beach Deformation....................................................................................................163
  • 6. CONTENTS-v-Chapter 11 Subsoil...........................................................................................................................................................16711.1 Method of Determining Geotechnical Conditions.........................................................................16711.1.1 Principles.................................................................................................................................16711.1.2 Selection of Soil Investigation Methods ..................................................................................16811.1.3 Standard Penetration Test ......................................................................................................16811.2 Physical Properties of Soils .............................................................................................................16811.2.1 Unit Weight of Soil...................................................................................................................16811.2.2 Classification of Soils ..............................................................................................................16911.2.3 Coefficient of Permeability of Soil ...........................................................................................16911.3 Mechanical Properties of Soils........................................................................................................17011.3.1 Elastic Constants ....................................................................................................................17011.3.2 Consolidation Properties.........................................................................................................17011.3.3 Shear Properties .....................................................................................................................17311.4 Angle of Internal Friction by N-value ..............................................................................................17511.5 Application of Soundings Other Than SPT....................................................................................17611.6 Dynamic Properties of Soils.............................................................................................................17811.6.1 Dynamic Modulus of Deformation...........................................................................................17811.6.2 Dynamic Strength Properties ..................................................................................................180Chapter 12 Earthquakes and Seismic Force...........................................................................................................18212.1 General................................................................................................................................................18212.2 Earthquake Resistance of Port and Harbor Facilities in Design................................................18212.3 Seismic Coefficient Method .............................................................................................................18412.4 Design Seismic Coefficient ..............................................................................................................18412.5 Seismic Response Analysis.............................................................................................................19012.6 Seismic Deformation Method ..........................................................................................................192Chapter 13 Liquefaction .................................................................................................................................................19513.1 General................................................................................................................................................19513.2 Prediction of Liquefaction.................................................................................................................19513.3 Countermeasures against Liquefaction .........................................................................................199Chapter 14 Earth Pressure and Water Pressure ...................................................................................................20014.1 Earth Pressure ...................................................................................................................................20014.2 Earth Pressure under Ordinary Conditions ...................................................................................20014.2.1 Earth Pressure of Sandy Soil under Ordinary Conditions.......................................................20014.2.2 Earth Pressure of Cohesive Soil under Ordinary Conditions ..................................................20114.3 Earth Pressure during Earthquake .................................................................................................20214.3.1 Earth Pressure of Sandy Soil during Earthquake....................................................................20214.3.2 Earth Pressure of Cohesive Soil during Earthquake...............................................................20414.3.3 Apparent Seismic Coefficient..................................................................................................20414.4 Water Pressure..................................................................................................................................20514.4.1 Residual Water Pressure ........................................................................................................20514.4.2 Dynamic Water Pressure during Earthquake..........................................................................205Chapter 15 Loads.............................................................................................................................................................20715.1 General................................................................................................................................................20715.2 Deadweight and Surcharge .............................................................................................................20715.3 Static Load..........................................................................................................................................20715.3.1 Static Load under Ordinary Conditions ...................................................................................20715.3.2 Static Load during Earthquake................................................................................................20815.3.3 Unevenly Distributed Load......................................................................................................20815.3.4 Snow Load ..............................................................................................................................20815.4 Live Load ............................................................................................................................................20915.4.1 Train Load...............................................................................................................................20915.4.2 Vehicle Load ...........................................................................................................................20915.4.3 Cargo Handling Equipment Load............................................................................................20915.4.4 Sidewalk Live Load .................................................................................................................209Chapter 16 Coefficient of Friction................................................................................................................................21016.1 General................................................................................................................................................210Part III MaterialsChapter 1 General .........................................................................................................................................................2111.1 Selection of Materials........................................................................................................................211
  • 7. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-vi-1.2 Safety of Structural Elements.......................................................................................................... 211Chapter 2 Steel...............................................................................................................................................................2122.1 Materials .............................................................................................................................................2122.2 Steel Meterial Constants Used in Design Calculation.................................................................2122.3 Allowable Stresses............................................................................................................................ 2122.3.1 General ...................................................................................................................................2122.3.2 Structural Steel .......................................................................................................................2122.3.3 Steel Piles and Steel Pipe Sheet Piles ...................................................................................2132.3.4 Steel Sheet Piles ....................................................................................................................2142.3.5 Cast Steel and Forged Steel...................................................................................................2142.3.6 Allowable Stresses for Steel at Welded Zones and Spliced Sections ....................................2142.3.7 Increase of Allowable Stresses...............................................................................................2152.4 Corrosion Control ..............................................................................................................................2162.4.1 General ...................................................................................................................................2162.4.2 Corrosion Rates of Steel Materials .........................................................................................2162.4.3 Corrosion Control Methods.....................................................................................................2172.4.4 Cathodic Protection Method ...................................................................................................217[1] Range of Application........................................................................................................217[2] Protective Potential..........................................................................................................218[3] Protective Current Density...............................................................................................2192.4.5 Coating Method ...................................................................................................................... 220[1] Extent of Application ........................................................................................................220[2] Applicable Methods..........................................................................................................220[3] Selection of Method .........................................................................................................220Chapter 3 Concrete....................................................................................................................................................... 2213.1 General ...............................................................................................................................................2213.2 Basics of Design Based on the Limit State Design Method.......................................................2213.3 Design Based on Allowable Stress Method..................................................................................2233.4 Concrete Materials............................................................................................................................ 2243.5 Concrete Quality and Performance................................................................................................ 2253.6 Underwater Concrete .......................................................................................................................227Chapter 4 Bituminous Materials................................................................................................................................2284.1 General ...............................................................................................................................................2284.2 Asphalt Mat ........................................................................................................................................2284.2.1 General ...................................................................................................................................2284.2.2 Materials ................................................................................................................................. 2284.2.3 Mix Proportioning....................................................................................................................2294.3 Paving Materials................................................................................................................................2294.4 Sand Mastic Asphalt.........................................................................................................................2294.4.1 General ...................................................................................................................................2294.4.2 Materials ................................................................................................................................. 2304.4.3 Mix Proportioning....................................................................................................................230Chapter 5 Stone ............................................................................................................................................................. 2315.1 General ...............................................................................................................................................2315.2 Rubble for Foundation...................................................................................................................... 2315.3 Backfilling Materials ..........................................................................................................................2315.4 Base Course Materials of Pavement .............................................................................................232Chapter 6 Timber ...........................................................................................................................................................2336.1 Quality of Timber...............................................................................................................................2336.1.1 Structural Timber ....................................................................................................................2336.1.2 Timber Piles............................................................................................................................ 2336.2 Allowable Stresses of Timber..........................................................................................................2336.2.1 General ...................................................................................................................................2336.2.2 Allowable Stresses of Structural Timber.................................................................................2336.3 Quality of Glued Laminated Timber ...............................................................................................2336.3.1 Allowable Stress for Glued Laminated Timber .......................................................................2336.4 Joining of Timber...............................................................................................................................2336.5 Maintenance of Timber.....................................................................................................................233Chapter 7 Other Materials...........................................................................................................................................2347.1 Metals Other Than Steel ..................................................................................................................2347.2 Plastics and Rubbers........................................................................................................................2347.3 Coating Materials ..............................................................................................................................236
  • 8. CONTENTS-vii-7.4 Grouting Materials .............................................................................................................................2377.4.1 General ...................................................................................................................................2377.4.2 Properties of Grouting Materials .............................................................................................237Chapter 8 Recyclable Resources .............................................................................................................................2388.1 General................................................................................................................................................2388.2 Slag......................................................................................................................................................2388.3 Coal Ash..............................................................................................................................................2398.4 Crashed Concrete .............................................................................................................................240Part IV Precast Concrete UnitsChapter 1 Caissons.......................................................................................................................................................2411.1 General................................................................................................................................................2411.2 Determination of Dimensions ..........................................................................................................2421.3 Floating Stability ................................................................................................................................2421.4 Design External Forces ....................................................................................................................2431.4.1 Combination of Loads and Load Factors ................................................................................2431.4.2 External Forces during Fabrication .........................................................................................2491.4.3 External Forces during Launching and Floating......................................................................2491.4.4 External Forces during Installation..........................................................................................2501.4.5 External Forces after Construction..........................................................................................250[1] Outer Walls.......................................................................................................................250[2] Bottom Slab......................................................................................................................251[3] Partition Walls and Others................................................................................................2531.5 Design of Members ...........................................................................................................................2541.5.1 Outer Wall ...............................................................................................................................2541.5.2 Partition Wall...........................................................................................................................2541.5.3 Bottom Slab.............................................................................................................................2541.5.4 Others .....................................................................................................................................2551.6 Design of Hooks for Suspension by Crane ...................................................................................255Chapter 2 L-Shaped Blocks........................................................................................................................................2562.1 General................................................................................................................................................2562.2 Determination of Dimensions ..........................................................................................................2562.3 Loads Acting on Members ...............................................................................................................2572.3.1 General ...................................................................................................................................2572.3.2 Earth Pressure ........................................................................................................................2582.3.3 Converted Loads for Design Calculation.................................................................................2582.4 Design of Members ...........................................................................................................................2592.4.1 Front Wall................................................................................................................................2592.4.2 Footing ....................................................................................................................................2592.4.3 Bottom Slab.............................................................................................................................2592.4.4 Buttress...................................................................................................................................2602.5 Design of Hooks for Suspension by Crane ...................................................................................260Chapter 3 Cellular Blocks............................................................................................................................................2613.1 General................................................................................................................................................2613.2 Determination of Dimensions ..........................................................................................................2613.2.1 Shape of Cellular Blocks.........................................................................................................2613.2.2 Determination of Dimensions..................................................................................................2613.3 Loads Acting on Cellular Blocks......................................................................................................2623.3.1 General ...................................................................................................................................2623.3.2 Earth Pressure of Filling and Residual Water Pressure..........................................................2623.3.3 Converted Loads for Design Calculation.................................................................................2643.4 Design of Members ...........................................................................................................................2643.4.1 Rectangular Cellular Blocks....................................................................................................2643.4.2 Other Types of Cellular Blocks................................................................................................265Chapter 4 Upright Wave-Absorbing Caissons......................................................................................................2674.1 General................................................................................................................................................2674.2 External Forces Acting on Members ..............................................................................................2674.3 Design of Members ...........................................................................................................................269Chapter 5 Hybrid Caissons.........................................................................................................................................2705.1 General................................................................................................................................................2705.2 Determination of Dimensions ..........................................................................................................270
  • 9. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-viii-5.3 Design External Forces....................................................................................................................2715.4 Design of Members...........................................................................................................................2715.4.1 Section Force..........................................................................................................................2715.4.2 Design of Composite Slabs ....................................................................................................2715.4.3 Design of SRC Members ........................................................................................................2715.4.4 Design of Partitions................................................................................................................. 2715.4.5 Design of Corners and Joints .................................................................................................2715.4.6 Safety against Fatigue Failure................................................................................................ 2725.5 Corrosion Control ..............................................................................................................................272Part V FoundationsChapter 1 General .........................................................................................................................................................273Chapter 2 Bearing Capacity of Shallow Foundations ........................................................................................2742.1 General ...............................................................................................................................................2742.2 Bearing Capacity of Foundation on Sandy Ground.....................................................................2742.3 Bearing Capacity of Foundation on Clayey Ground.................................................................... 2752.4 Bearing Capacity of Multilayered Ground ..................................................................................... 2762.5 Bearing Capacity for Eccentric and Inclined Loads.....................................................................277Chapter 3 Bearing Capacity of Deep Foundations .............................................................................................2803.1 General ...............................................................................................................................................2803.2 Vertical Bearing Capacity................................................................................................................. 2803.3 Lateral Bearing Capacity..................................................................................................................281Chapter 4 Bearing Capacity of Pile Foundations ................................................................................................ 2844.1 Allowable Axial Bearing Capacity of Piles..................................................................................... 2844.1.1 General ...................................................................................................................................2844.1.2 Standard Allowable Axial Bearing Capacity............................................................................2844.1.3 Ultimate Axial Bearing Capacity of Single Piles......................................................................2854.1.4 Estimation of Ultimate Axial Bearing Capacity by Loading Tests ...........................................2854.1.5 Estimation of Ultimate Axial Bearing Capacity by Static Bearing Capacity Formulas ............ 2864.1.6 Examination of Compressive Stress of Pile Materials ............................................................2884.1.7 Decrease of Bearing Capacity Due to Joints ..........................................................................2884.1.8 Decrease of Bearing Capacity Due to Slenderness Ratio ......................................................2884.1.9 Bearing Capacity of Pile Group ..............................................................................................2884.1.10 Examination of Negative Skin Friction ....................................................................................2904.1.11 Examination of Settlement of Piles .........................................................................................2914.2 Allowable Pulling Resistance of Piles ............................................................................................2914.2.1 General ...................................................................................................................................2914.2.2 Standard Allowable Pulling Resistance ..................................................................................2924.2.3 Maximum Pulling Resistance of Single Pile............................................................................2924.2.4 Examination of Tensile Stress of Pile Materials......................................................................2934.2.5 Matters to Be Considered for Obtaining Allowable Pulling Resistance of Piles......................2934.3 Allowable Lateral Bearing Capacity of Piles .................................................................................2934.3.1 General ...................................................................................................................................2934.3.2 Estimation of Allowable Lateral Bearing Capacity of Piles .....................................................2954.3.3 Estimation of Pile Behavior Using Loading Tests ...................................................................2954.3.4 Estimation of Pile Behavior Using Analytical Methods ...........................................................2954.3.5 Consideration of Pile Group Action.........................................................................................3014.3.6 Lateral Bearing Capacity of Coupled Piles .............................................................................3014.4 Pile Design in General...................................................................................................................... 3044.4.1 Load Sharing ..........................................................................................................................3044.4.2 Load Distribution.....................................................................................................................3054.4.3 Distance between Centers of Piles.........................................................................................3054.4.4 Allowable Stresses for Pile Materials......................................................................................3054.5 Detailed Design ................................................................................................................................. 3064.5.1 Examination of Loads during Construction .............................................................................3064.5.2 Design of Joints between Piles and Structure ........................................................................3074.5.3 Joints of Piles..........................................................................................................................3084.5.4 Change of Plate Thickness or Materials of Steel Pipe Piles................................................... 3084.5.5 Other Points for Caution in Design .........................................................................................308Chapter 5 Settlement of Foundations .....................................................................................................................3105.1 Stress in Soil Mass ...........................................................................................................................3105.2 Immediate Settlement.......................................................................................................................310
  • 10. CONTENTS-ix-5.3 Consolidation Settlement .................................................................................................................3105.4 Lateral Displacement ........................................................................................................................3125.5 Differential Settlements ....................................................................................................................312Chapter 6 Stability of Slopes......................................................................................................................................3146.1 General................................................................................................................................................3146.2 Stability Analysis................................................................................................................................3156.2.1 Stability Analysis Using Circular Slip Surface Method ............................................................3156.2.2 Stability Analysis Assuming Slip Surfaces Other Than Circular Arc Slip Surface...................316Chapter 7 Soil Improvement Methods.....................................................................................................................3187.1 General................................................................................................................................................3187.2 Replacement Method........................................................................................................................3187.3 Vertical Drain Method .......................................................................................................................3187.3.1 Principle of Design ..................................................................................................................3187.3.2 Determination of Height and Width of Fill................................................................................319[1] Height and Width of Fill Required for Soil Improvement ..................................................319[2] Height and Width of Fill Required for Stability of Fill Embankment..................................3197.3.3 Design of Drain Piles...............................................................................................................319[1] Drain Piles and Sand Mat.................................................................................................319[2] Interval of Drain Piles .......................................................................................................3207.4 Deep Mixing Method .........................................................................................................................3227.4.1 Principle of Design ..................................................................................................................322[1] Scope of Application.........................................................................................................322[2] Basic Concept ..................................................................................................................3237.4.2 Assumptions for Dimensions of Stabilized Body.....................................................................323[1] Mixture Design of Stabilized Soil......................................................................................323[2] Allowable Stress of Stabilized Body.................................................................................3247.4.3 Calculation of External Forces ................................................................................................3257.5 Lightweight Treated Soil Method ....................................................................................................3267.5.1 Outline of Lightweight Treated Soil Method ............................................................................3267.5.2 Basic Design Concept.............................................................................................................3267.5.3 Mixture Design of Treated Soil................................................................................................3277.5.4 Examination of Area to Be Treated.........................................................................................3287.5.5 Workability Verification Tests..................................................................................................3287.6 Replacement Method with Granulated Blast Furnace Slag........................................................3287.6.1 Principle of Design ..................................................................................................................3287.6.2 Physical Properties of Granulated Blast Furnace Slag ...........................................................3287.7 Premixing Method..............................................................................................................................3297.7.1 Principle of Design ..................................................................................................................329[1] Scope of Application.........................................................................................................329[2] Consideration for Design..................................................................................................3297.7.2 Preliminary Survey..................................................................................................................3297.7.3 Determination of Strength of Treated Soil...............................................................................3307.7.4 Mixture Design of Treated Soil................................................................................................3307.7.5 Examination of Area of Improvement......................................................................................3317.8 Active Earth Pressure of Solidified Geotechnical Materials........................................................3337.8.1 Scope of Application ...............................................................................................................3337.8.2 Active Earth Pressure .............................................................................................................333[1] Outline..............................................................................................................................333[2] Strength Parameters ........................................................................................................334[3] Calculation of Active Earth Pressure................................................................................334[4] Case of Limited Area of Subsoil Improvement.................................................................3357.9 Sand Compaction Pile Method (for Sandy Subsoil).....................................................................3367.9.1 Principle of Design ..................................................................................................................3367.9.2 Sand Volume to Be Supplied ..................................................................................................3367.9.3 Design Based on Trial Execution............................................................................................3387.10 Sand Compaction Pile Method (for Cohesive Subsoil) ...............................................................3397.10.1 Principle of Design ..................................................................................................................339[1] Scope of Application.........................................................................................................339[2] Basic Concept ..................................................................................................................3397.10.2 Strength and Permeability of Sand Piles.................................................................................3397.10.3 Shear Strength of Improved Subsoil .......................................................................................3397.10.4 Stability Analysis .....................................................................................................................3407.10.5 Examining Consolidation.........................................................................................................341
  • 11. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-x-Part VI Navigation Channels and BasinsChapter 1 General .........................................................................................................................................................345Chapter 2 Navigation Channels ................................................................................................................................3462.1 General ...............................................................................................................................................3462.2 Alignment of Navigation Channel ..................................................................................................3462.3 Width of Navigation Channel........................................................................................................... 3472.4 Depth of Navigation Channel ..........................................................................................................3482.5 Length of Navigation Channel at Harbor Entrance......................................................................3482.6 Calmness of Navigation Channel ...................................................................................................348Chapter 3 Navigation Channels outside Breakwaters .......................................................................................3503.1 General ...............................................................................................................................................3503.2 Width of Navigation Channel........................................................................................................... 3503.3 Depth of Navigation Channel ..........................................................................................................350Chapter 4 Basins............................................................................................................................................................3514.1 General ...............................................................................................................................................3514.2 Location and Area of Basin .............................................................................................................3514.2.1 Location ..................................................................................................................................3514.2.2 Area of Basin Used for Anchorage or Mooring .......................................................................3514.2.3 Area of Basin Used for Ship Maneuvering..............................................................................352[1] Turning Basin...................................................................................................................352[2] Mooring / Unmooring Basin .............................................................................................3534.3 Depth of Basin ...................................................................................................................................3534.4 Calmness of Basin............................................................................................................................ 3534.5 Timber Sorting Pond.........................................................................................................................354Chapter 5 Small Craft Basins.....................................................................................................................................355Chapter 6 Maintenance of Navigation Channels and Basins..........................................................................3556.1 General ...............................................................................................................................................355Part VII Protective Facilities for HarborsChapter 1 General .........................................................................................................................................................3571.1 General Consideration .....................................................................................................................3571.2 Maintenance.......................................................................................................................................357Chapter 2 Breakwaters ................................................................................................................................................3582.1 General ...............................................................................................................................................3582.2 Layout of Breakwaters...................................................................................................................... 3582.3 Design Conditions of Breakwaters .................................................................................................3592.4 Selection of Structural Types ..........................................................................................................3592.5 Determination of Cross Section ......................................................................................................3622.5.1 Upright Breakwater................................................................................................................. 3622.5.2 Composite Breakwater ........................................................................................................... 3632.5.3 Sloping Breakwater................................................................................................................. 3632.5.4 Caisson Type Breakwater Covered with Wave-Dissipating Concrete Blocks ........................3642.6 External Forces for Stability Calculation........................................................................................3642.6.1 General ...................................................................................................................................3642.6.2 Wave Forces...........................................................................................................................3652.6.3 Hydrostatic Pressure ..............................................................................................................3652.6.4 Buoyancy................................................................................................................................3652.6.5 Deadweight.............................................................................................................................3652.6.6 Stability during Earthuakes.....................................................................................................3652.7 Stability Calculation...........................................................................................................................3652.7.1 Stability Calculation of Upright Section...................................................................................3652.7.2 Stability Calculation of Sloping Section ..................................................................................3692.7.3 Stability Calculation of Whole Section ....................................................................................3692.7.4 Stability Calculation for Head and Corner of Breakwater .......................................................3692.8 Details of Structures .........................................................................................................................3702.8.1 Upright Breakwater................................................................................................................. 3702.8.2 Composite Breakwater ........................................................................................................... 3712.8.3 Sloping Breakwater................................................................................................................. 372
  • 12. CONTENTS-xi-2.8.4 Caisson Type Breakwater Covered with Wave-Dissipating Concrete Blocks.........................3722.9 Detailed Design of Upright Section.................................................................................................3722.10 Breakwaters for Timber-Handling Facilities ..................................................................................3722.10.1 Breakwaters for Timber Storage Ponds and Timber Sorting Ponds .......................................3722.10.2 Fences to Prevent Timber Drifting ..........................................................................................3732.11 Storm Surge Protection Breakwater...............................................................................................3732.12 Tsunami Protection Breakwater......................................................................................................373Chapter 3 Other Types of Breakwaters ..................................................................................................................3763.1 Selection of Structural Type.............................................................................................................3763.2 Gravity Type Special Breakwaters..................................................................................................3773.2.1 General ...................................................................................................................................3773.2.2 Upright Wave-Absorbing Block Breakwater............................................................................378[1] General.............................................................................................................................378[2] Crest Elevation.................................................................................................................378[3] Wave Force......................................................................................................................3793.2.3 Wave-Absorbing Caisson Breakwater ....................................................................................379[1] General.............................................................................................................................379[2] Determination of Target Waves to Be Absorbed..............................................................380[3] Determination of Dimensions for Wave-Absorbing Section .............................................380[4] Wave Force for Examination of Structural Stability..........................................................380[5] Wave Force for Design of Structural Members ................................................................3803.2.4 Sloping-Top Caisson Breakwater............................................................................................380[1] General.............................................................................................................................380[2] Wave Force......................................................................................................................3813.3 Non-Gravity Type Breakwaters .......................................................................................................3823.3.1 Curtain Wall Breakwater .........................................................................................................382[1] General.............................................................................................................................382[2] Wave Force......................................................................................................................384[3] Design of Piles .................................................................................................................3843.3.2 Floating Breakwater ................................................................................................................384[1] General.............................................................................................................................384[2] Selection of Design Conditions ........................................................................................385[3] Design of Mooring System ...............................................................................................385[4] Design of Floating Body Structure....................................................................................386Chapter 4 Locks..............................................................................................................................................................3884.1 Selection of Location.........................................................................................................................3884.2 Size and Layout of Lock ...................................................................................................................3884.3 Selection of Structural Type.............................................................................................................3894.3.1 Gate ........................................................................................................................................3894.3.2 Lock Chamber.........................................................................................................................3894.4 External Forces and Loads Acting on Lock...................................................................................3894.5 Pumping and Drainage System ......................................................................................................3894.6 Auxiliary Facilities..............................................................................................................................389Chapter 5 Facilities to Prevent Shoaling and Siltation.......................................................................................3905.1 General................................................................................................................................................3905.2 Jetty .....................................................................................................................................................3905.2.1 Layout of Jetty.........................................................................................................................3905.2.2 Details of Jetty.........................................................................................................................3915.3 Group of Groins .................................................................................................................................3925.4 Training Jetties...................................................................................................................................3925.4.1 Layout of Training Jetties........................................................................................................3925.4.2 Water Depth at Tip of Training Jetty .......................................................................................3935.4.3 Structure of Training Jetty.......................................................................................................3935.5 Facilities to Trap Littoral Transport and Sediment Flowing out of Rivers.................................3935.6 Countermeasures against Wind-Blown Sand...............................................................................3945.6.1 General ...................................................................................................................................3945.6.2 Selection of Countermeasures................................................................................................394Chapter 6 Revetments..................................................................................................................................................3966.1 Principle of Design ............................................................................................................................3966.2 Design Conditions .............................................................................................................................3966.3 Structural Stability..............................................................................................................................3986.4 Determination of Cross Section ......................................................................................................3986.5 Details..................................................................................................................................................398
  • 13. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-xii-Part VIII Mooring FacilitiesChapter 1 General .........................................................................................................................................................4011.1 General Consideration .....................................................................................................................4011.2 Maintenance of Mooring Facilities..................................................................................................401Chapter 2 Dimensions of Mooring Facilities..........................................................................................................4022.1 Length and Water Depth of Berths.................................................................................................4022.2 Crown Heights of Mooring Facilities...............................................................................................4052.3 Ship Clearance for Mooring Facilities ............................................................................................4052.4 Design Water Depth .........................................................................................................................4052.5 Protection against Scouring.............................................................................................................4062.6 Ancillary Facilities..............................................................................................................................406Chapter 3 Structural Types of Mooring Facilities ................................................................................................ 407Chapter 4 Gravity Type Quaywalls ..........................................................................................................................4084.1 Principle of Design............................................................................................................................ 4084.2 External Forces and Loads Acting on Walls.................................................................................4084.3 Stability Calculations.........................................................................................................................4104.3.1 Items to Be Considered in Stability Calculations .................................................................... 4104.3.2 Examination against Sliding of Wall........................................................................................4104.3.3 Examination Concerning Bearing Capacity of Foundation ..................................................... 4114.3.4 Examination Concerning Overturning of Wall......................................................................... 4114.3.5 Examination on Soft Foundation............................................................................................. 4114.4 Stability Calculations of Cellular Concrete Blocks .......................................................................4124.5 Effects of Backfill...............................................................................................................................4134.6 Detailed Design ................................................................................................................................. 414Chapter 5 Sheet Pile Quaywalls ...............................................................................................................................4155.1 General ...............................................................................................................................................4155.2 External Forces Acting on Sheet Pile Wall ...................................................................................4155.2.1 External Forces to Be Considered..........................................................................................4155.3 Design of Sheet Pile Wall ................................................................................................................4175.3.1 Setting Level of Tie Rod .........................................................................................................4175.3.2 Embedded Length of Sheet Piles ...........................................................................................4175.3.3 Bending Moment of Sheet Piles and Reaction at Tie Rod Setting Point ................................4185.3.4 Cross Section of Sheet Piles ..................................................................................................4195.3.5 Consideration of the Effect of Section Rigidity of Sheet Piles ................................................4195.4 Design of Tie Rods ...........................................................................................................................4245.4.1 Tension of Tie Rod ................................................................................................................. 4245.4.2 Cross Section of Tie Rod........................................................................................................4245.5 Design of Wale ..................................................................................................................................4255.6 Examination for Circular Slip........................................................................................................... 4255.7 Design of Anchorage Work..............................................................................................................4265.7.1 Selection of Structural Type of Anchorage Work.................................................................... 4265.7.2 Location of Anchorage Work ..................................................................................................4265.7.3 Design of Anchorage Work.....................................................................................................4275.8 Detailed Design ................................................................................................................................. 4285.8.1 Coping ....................................................................................................................................4285.8.2 Fitting of Tie Rods and Wale to Sheet Piles ...........................................................................4295.8.3 Tie Rod ...................................................................................................................................4295.8.4 Fitting of Tie Rods to Anchorage Work...................................................................................4295.9 Special Notes for Design of Sheet Pile Wall on Soft Ground.....................................................429Chapter 6 Sheet Pile Quaywalls with Relieving Platform .................................................................................4316.1 Scope of Application.........................................................................................................................4316.2 Principles of Design ..........................................................................................................................4316.3 Determination of Height and Width of Relieving Platform ..........................................................4316.4 Earth Pressure and Residual Water Pressure Acting on Sheet Piles ......................................4326.5 Design of Sheet Pile Wall ................................................................................................................4326.5.1 Embedded Length of Sheet Piles ...........................................................................................4326.5.2 Cross Section of Sheet Piles ..................................................................................................4336.6 Design of Relieving Platform and Relieving Platform Piles........................................................4336.6.1 External Forces Acting on Relieving Platform ........................................................................4336.6.2 Design of Relieving Platform ..................................................................................................4336.6.3 Design of Piles........................................................................................................................434
  • 14. CONTENTS-xiii-6.7 Examination of Stability as Gravity Type Wall ..............................................................................4346.8 Examination of Stability against Circular Slip................................................................................435Chapter 7 Steel Sheet Pile Cellular-Bulkhead Quaywalls ................................................................................4367.1 Principle of Design ............................................................................................................................4367.2 External Forces Acting on Steel Sheet Pile Cellular-Bulkhead Quaywall ................................4377.3 Examination of Wall Width against Shear Deformation ..............................................................4387.3.1 General ...................................................................................................................................4387.3.2 Equivalent Width of Wall .........................................................................................................4397.3.3 Calculation of Deformation Moment........................................................................................4397.3.4 Calculation of Resisting Moment.............................................................................................4407.4 Examination of Stability of Wall Body as a Whole........................................................................4437.4.1 General ...................................................................................................................................4437.4.2 Modulus of Subgrade Reaction...............................................................................................4437.4.3 Calculation of Subgrade Reaction and Wall Displacement.....................................................4437.5 Examination of Bearing Capacity of the Ground ..........................................................................4487.6 Examination against Sliding of Wall ...............................................................................................4487.7 Examination of Displacement of Wall Top.....................................................................................4487.8 Examination of Stability against Circular Slip................................................................................4497.9 Layout of Cells and Arcs ..................................................................................................................4497.10 Calculation of Hoop Tension............................................................................................................4497.11 Design of T-Shaped Sheet Pile.......................................................................................................4507.11.1 General ...................................................................................................................................4507.11.2 Structure of T-Shaped Sheet Pile ...........................................................................................4507.12 Detailed Design..................................................................................................................................4517.12.1 Design of Pile to Support Coping............................................................................................4517.12.2 Design of Coping.....................................................................................................................451Chapter 8 Steel Plate Cellular-Bulkhead Quaywalls ..........................................................................................4528.1 Scope of Application .........................................................................................................................4528.2 Placement-Type Steel Plate Cellular-Bulkhead Quaywalls........................................................4528.2.1 Principle of Design ..................................................................................................................4528.2.2 External Forces Acting on Steel Plate Cellular-Bulkhead .......................................................4538.2.3 Examination of Wall Width against Shear Deformation ..........................................................4538.2.4 Examination of Stability of Wall Body as a Whole...................................................................4548.2.5 Examination of Bearing Capacity of the Ground.....................................................................4558.2.6 Examination of Stability against Circular Slip..........................................................................4558.2.7 Determination of Thickness of Steel Plate of Cell Shell..........................................................4558.2.8 Layout of Cells and Arcs .........................................................................................................4568.2.9 Detailed Design.......................................................................................................................4568.3 Embedded-Type Steel Plate Cellular-Bulkhead Quaywalls........................................................4568.3.1 Principle of Design ..................................................................................................................4568.3.2 External Forces Acting on Embedded-Type Steel Plate Celluler-Bulkhead............................4578.3.3 Examination of Wall Width against Shear Deformation ..........................................................4578.3.4 Examination of Stability of Wall Body as a Whole...................................................................4588.3.5 Examination of Bearing Capacity of the Ground.....................................................................4588.3.6 Examination against Sliding of Wall........................................................................................4588.3.7 Examination of Displacement of Wall Top ..............................................................................4588.3.8 Examination of Stability against Circular Slip..........................................................................4588.3.9 Layout of Cells and Arcs .........................................................................................................4588.3.10 Determination of Plate Thickness of Cell Shell and Arc Section.............................................4588.3.11 Joints and Stiffeners................................................................................................................4598.3.12 Detailed Design.......................................................................................................................459Chapter 9 Open-Type Wharves on Vertical Piles................................................................................................4609.1 Principle of Design ............................................................................................................................4609.2 Layout and Dimensions....................................................................................................................4629.2.1 Size of Deck Block and Layout of Piles...................................................................................4629.2.2 Dimensions of Superstructure.................................................................................................4629.2.3 Arrangement of Fenders and Bollards ....................................................................................4639.3 External Forces Acting on Open-Type Wharf...............................................................................4639.3.1 Design External Forces...........................................................................................................4639.3.2 Calculation of Fender Reaction Force.....................................................................................4649.4 Assumptions Concerning Sea Bottom Ground.............................................................................4649.4.1 Determination of Slope Inclination ..........................................................................................4649.4.2 Virtual Ground Surface............................................................................................................4659.5 Design of Piles ...................................................................................................................................465
  • 15. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-xiv-9.5.1 General ...................................................................................................................................4659.5.2 Coefficient of Horizontal Subgrade Reaction..........................................................................4659.5.3 Virtual Fixed Point...................................................................................................................4669.5.4 Member Forces Acting on Individual Piles..............................................................................4669.5.5 Cross-Sectional Stresses of Piles...........................................................................................4689.5.6 Examination of Embedded Length for Bearing Capacity ........................................................4689.5.7 Examination of Embedded Length for Lateral Resistance......................................................4689.5.8 Examination of Pile Joints.......................................................................................................4689.5.9 Change of Plate Thickness or Material of Steel Pipe Pile ......................................................4689.6 Examination of Earthquake-Resistant Performance ...................................................................4699.6.1 Assumption of Cross Section for Earthquake-Resistant Performance Examination ..............4709.6.2 Examination Method of Earthquake-Resistant Performance..................................................4709.6.3 Determination of Seismic Motion for Examination of Earthquake-Resistant Performance.....4719.6.4 Examination of Load Carrying Capacity Using Simplified Method..........................................4739.6.5 Examination of Load Carrying Capacity Using Elasto-Plastic Analysis .................................. 4759.7 Design of Earth-Retaining Section .................................................................................................4779.8 Examination of Stability against Circular Slip ............................................................................... 4779.9 Detailed Design ................................................................................................................................. 4789.9.1 Load Combinations for Superstructure Design.......................................................................4789.9.2 Calculation of Reinforcing Bar Arrangement of Superstructure..............................................4789.9.3 Design of Pile Head ................................................................................................................478Chapter 10 Open-Type Wharves on Coupled Raking Piles............................................................................... 48010.1 Principle of Design............................................................................................................................ 48010.2 Layout and Dimensions....................................................................................................................48110.2.1 Size of Deck Block and Layout of Piles ..................................................................................48110.2.2 Dimensions of Supersutructure ..............................................................................................48110.2.3 Arrangement of Fenders and Bollards....................................................................................48110.3 External Forces Acting on Open-Type Wharf on Coupled Raking Piles.................................. 48110.3.1 Design External Forces ..........................................................................................................48110.3.2 Calculation of Fender Reaction Force ....................................................................................48110.4 Assumptions Concerning Sea Bottom Ground.............................................................................48110.4.1 Determination of Slope Inclination .......................................................................................... 48110.4.2 Virtual Ground Surface ........................................................................................................... 48110.5 Determination of Forces Acting on Piles and Cross Sections of Piles .....................................48110.5.1 Horizontal Force Transmitted to Heads of Coupled Raking Piles...........................................48110.5.2 Vertical Load Transmitted to Heads of Coupled Raking Piles ................................................48310.5.3 Pushing-In and Pulling-Out Forces of Coupled Raking Piles .................................................48310.5.4 Cross-Sectional Stresses of Piles...........................................................................................48310.6 Examination of Strength of Wharf in the Direction of Its Face Line ..........................................48410.7 Embedded Length of Raking Pile...................................................................................................48410.8 Design of Earth-Retaining Section .................................................................................................48410.9 Examination of Stability against Circular Slip ............................................................................... 48410.10 Detailed Design ................................................................................................................................. 484Chapter 11 Detached Pier.............................................................................................................................................48511.1 Scope of Application.........................................................................................................................48511.2 Principle of Design............................................................................................................................ 48511.3 Design of Detached Pier ..................................................................................................................48511.3.1 Layout and Dimensions ..........................................................................................................48511.3.2 External Forces and Loads.....................................................................................................48511.3.3 Design of Piers .......................................................................................................................48611.3.4 Design of Girder...................................................................................................................... 48611.4 Ancillary Equipment..........................................................................................................................48611.5 Detailed Design ................................................................................................................................. 48611.5.1 Superstructure ........................................................................................................................48611.5.2 Gangways..............................................................................................................................486Chapter 12 Floating Piers..............................................................................................................................................48712.1 Scope of Application.........................................................................................................................48712.2 Principle of Design............................................................................................................................ 48812.3 Design of Pontoon.............................................................................................................................48812.3.1 Dimensions of Pontoon........................................................................................................... 48812.3.2 External Forces and Loads Acting on Pontoon ......................................................................48812.3.3 Stability of Pontoon................................................................................................................. 48812.3.4 Design of Individual Parts of Pontoon..................................................................................... 48912.4 Design of Mooring System...............................................................................................................490
  • 16. CONTENTS-xv-12.4.1 Mooring Method ......................................................................................................................49012.4.2 Design of Mooring Chain.........................................................................................................490[1] Design External Forces....................................................................................................490[2] Setting of Chain................................................................................................................490[3] Diameter of Chain ............................................................................................................49012.4.3 Design of Mooring Anchor.......................................................................................................492[1] Design External Forces....................................................................................................492[2] Design of Mooring Anchor................................................................................................49212.5 Design of Access Bridge and Gangway ........................................................................................49212.5.1 Dimensions and Inclination .....................................................................................................49212.5.2 Design of Access Bridge and Gangway..................................................................................49312.5.3 Adjusting Tower ......................................................................................................................493Chapter 13 Dolphins........................................................................................................................................................49413.1 Principle of Design ............................................................................................................................49413.2 Layout..................................................................................................................................................49413.3 External Forces Acting on Dolphins ...............................................................................................49513.4 Pile Type Dolphins ............................................................................................................................49513.5 Steel Cellular-Bulkhead Type Dolphins .........................................................................................49513.6 Caisson Type Dolphins.....................................................................................................................496Chapter 14 Slipways and Shallow Draft Quays......................................................................................................49714.1 Slipways..............................................................................................................................................49714.1.1 Principle of Design ..................................................................................................................49714.1.2 Location of Slipway .................................................................................................................49714.1.3 Dimensions of Individual Parts................................................................................................497[1] Elevations of Individual Parts ...........................................................................................497[2] Slipway Length and Background Space...........................................................................498[3] Water Depth .....................................................................................................................498[4] Gradient of Slipway ..........................................................................................................498[5] Basin Area........................................................................................................................49814.1.4 Front Wall and Pavement........................................................................................................499[1] Front Wall.........................................................................................................................499[2] Pavement .........................................................................................................................49914.2 Shallow Draft Quay ...........................................................................................................................499Chapter 15 Air-Cushion Vehicle Landing Facilities ...............................................................................................50015.1 Principle of Design ............................................................................................................................50015.2 Location...............................................................................................................................................50115.3 Air-Cushion Vehicle Landing Facilities...........................................................................................50115.4 Dimensions of Individual Parts........................................................................................................501Chapter 16 Mooring Buoys and Mooring Posts......................................................................................................50216.1 Mooring Buoys ...................................................................................................................................50216.1.1 Principle of Design ..................................................................................................................50216.1.2 Tractive Force Acting on Mooring Buoy..................................................................................50316.1.3 Design of Individual Parts of Mooring Buoy ............................................................................504[1] Mooring Anchor................................................................................................................504[2] Sinker and Sinker Chain...................................................................................................504[3] Ground Chain...................................................................................................................505[4] Main Chain .......................................................................................................................506[5] Floating Body ...................................................................................................................50716.2 Mooring Posts ....................................................................................................................................507Chapter 17 Other Types of Mooring Facilities.........................................................................................................50817.1 Quaywall of Wave-Absorbing Type ................................................................................................50817.1.1 Principle of Design ..................................................................................................................50817.1.2 Determination of Structural Form............................................................................................50817.2 Cantilever Sheet Pile Quaywall.......................................................................................................50917.2.1 Principle of Design ..................................................................................................................50917.2.2 External Forces Acting on Sheet Pile Wall..............................................................................51017.2.3 Determination of Cross Section of Sheet Piles .......................................................................51117.2.4 Determination of Embedded Length of Sheet Piles ................................................................51117.2.5 Examination of Displacement of Sheet Pile Crown.................................................................51117.2.6 External Forces during Construction.......................................................................................51217.2.7 Detailed Design.......................................................................................................................51217.3 Sheet Pile Quaywall with Batter Anchor Piles ..............................................................................51217.3.1 Principle of Design ..................................................................................................................512
  • 17. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-xvi-17.3.2 External Forces Acting on Sheet Pile Wall with Batter Anchor Piles ......................................51317.3.3 Calculation of Horizontal and Vertical Forces Acting on Connecting Point ............................51317.3.4 Determination of Cross Sections of Sheet Pile and Batter Anchor Pile.................................. 51317.3.5 Determination of Embedded Lengths of Sheet Pile and Batter Anchor Pile...........................51317.3.6 Detailed Design ...................................................................................................................... 51317.4 Sheet Pile Quaywall with Batter Piles in Front .............................................................................51417.4.1 Principle of Design..................................................................................................................51417.4.2 Layout and Dimensions ..........................................................................................................51517.4.3 Design of Sheet Pile Wall .......................................................................................................51517.4.4 Design of Open-Type Superstructure ..................................................................................... 51517.4.5 Embedded Length ..................................................................................................................51617.4.6 Detailed Design ...................................................................................................................... 51617.5 Double Sheet Pile Quaywall............................................................................................................51617.5.1 Principle of Design..................................................................................................................51617.5.2 External Forces Acting on Double Sheet Pile Quaywall ......................................................... 51717.5.3 Design of Double Sheet Pile Quaywall ...................................................................................517Chapter 18 Transitional Parts of Quaywalls ............................................................................................................51918.1 Principle of Design............................................................................................................................ 51918.2 Transitional Part Where Frontal Water Depth Varies..................................................................51918.3 Transitional Part Where Quaywalls of Different Type Are Connected .....................................51918.4 Outward Projecting Corner..............................................................................................................519Chapter 19 Ancillary Facilities...................................................................................................................................... 52019.1 General ...............................................................................................................................................52019.2 Mooring Equipment...........................................................................................................................52019.3 Mooring Posts, Bollards, and Mooring Rings ............................................................................... 52019.3.1 General ...................................................................................................................................52019.3.2 Arrangement of Mooring Posts, Bollards and Mooring Rings.................................................52119.3.3 Tractive Force of Vessel .........................................................................................................52119.3.4 Structure ................................................................................................................................. 52219.4 Fender System ..................................................................................................................................52219.4.1 General ...................................................................................................................................52219.4.2 Arrangement of Fenders.........................................................................................................52319.4.3 Berthing Energy of Vessel ......................................................................................................52319.4.4 Selection of Fender................................................................................................................. 52319.5 Safety Facilities ................................................................................................................................. 52519.5.1 General ...................................................................................................................................52519.5.2 Skirt Guard..............................................................................................................................52519.5.3 Fence and Rope .....................................................................................................................52519.5.4 Signs or Notices...................................................................................................................... 52519.5.5 Curbing ...................................................................................................................................52519.5.6 Fire Fighting Equipment and Alarm Systems ......................................................................... 52519.6 Service Facilities ...............................................................................................................................52519.6.1 General ...................................................................................................................................52519.6.2 Lighting Facilities ....................................................................................................................52519.6.3 Facilities for Passenger Embarkation and Disembarkation ....................................................52519.6.4 Vehicle Ramp .........................................................................................................................52619.6.5 Water Supply Facilities ........................................................................................................... 52619.6.6 Drainage Facilities ..................................................................................................................52619.6.7 Fueling and Electric Power Supply Facilities ..........................................................................52619.6.8 Signs or Notices...................................................................................................................... 52719.7 Stairways and Ladders.....................................................................................................................52719.8 Lifesaving Facilities...........................................................................................................................52719.9 Curbing ...............................................................................................................................................52719.10 Vehicle Ramp.....................................................................................................................................52719.11 Signs, Notices and Protective Fences...........................................................................................52719.11.1 General ...................................................................................................................................52719.11.2 Provision of Signs ...................................................................................................................52719.11.3 Types and Location of Signs ..................................................................................................52819.11.4 Position of Sign.......................................................................................................................52819.11.5 Structure of Sign .....................................................................................................................52919.11.6 Materials ................................................................................................................................. 53019.11.7 Maintenance and Management ..............................................................................................53019.11.8 Protective Fences ...................................................................................................................53019.11.9 Barricades...............................................................................................................................531
  • 18. CONTENTS-xvii-19.12 Lighting Facilities ...............................................................................................................................53119.12.1 General ...................................................................................................................................53119.12.2 Standard Intensity of Illumination............................................................................................531[1] Definition ..........................................................................................................................531[2] Standard Intensity of Illumination for Outdoor Lighting ....................................................531[3] Standard Intensity of Illumination for Indoor Lighting .......................................................53219.12.3 Selection of Light Source ........................................................................................................53219.12.4 Selection of Lighting Equipment..............................................................................................534[1] Outdoor Lighting...............................................................................................................534[2] Indoor Lighting..................................................................................................................53419.12.5 Design of Lighting ...................................................................................................................53519.12.6 Maintenance and Management...............................................................................................537[1] Inspections .......................................................................................................................537[2] Cleaning and Repair.........................................................................................................538Chapter 20 Aprons ...........................................................................................................................................................54020.1 Principle of Design ............................................................................................................................54020.2 Type of Apron.....................................................................................................................................54020.2.1 Width ......................................................................................................................................54020.2.2 Gradient ..................................................................................................................................54020.2.3 Type of Pavement...................................................................................................................54020.3 Countermeasures against Settlement of Apron............................................................................54020.4 Load Conditions.................................................................................................................................54120.5 Design of Concrete Pavement ........................................................................................................54120.5.1 Design Conditions...................................................................................................................54120.5.2 Composition of Pavement.......................................................................................................54220.5.3 Joints.......................................................................................................................................54520.5.4 Tie-Bar and Slip-Bar................................................................................................................54720.5.5 End Protection.........................................................................................................................54720.6 Design of Asphalt Pavement ...........................................................................................................54720.6.1 Design Conditions...................................................................................................................54720.6.2 Composition of Pavement.......................................................................................................54820.6.3 End Protection.........................................................................................................................55120.7 Design of Concrete Block Pavement..............................................................................................55120.7.1 Design Conditions...................................................................................................................55120.7.2 Composition of Pavement.......................................................................................................55220.7.3 Joints.......................................................................................................................................553Chapter 21 Foundation for Cargo Handling Equipment.......................................................................................55421.1 Principle of Design ............................................................................................................................55421.2 External Forces Acting on Foundation...........................................................................................55421.3 Design of Foundation with Piles......................................................................................................55521.3.1 Concrete Beam .......................................................................................................................55521.3.2 Bearing Capacity of Piles........................................................................................................55521.4 Design of Foundation without Piles ................................................................................................55621.4.1 Examination of Effects on Wharf.............................................................................................55621.4.2 Concrete Beam .......................................................................................................................556Part IX Other Port FacilitiesChapter 1 Port Traffic Facilities .................................................................................................................................5591.1 General................................................................................................................................................5591.1.1 Scope of Application ...............................................................................................................5591.1.2 Operation and Maintenance of Facilities for Land Traffic........................................................5591.2 Roads ..................................................................................................................................................5591.2.1 General ...................................................................................................................................5591.2.2 Design Vehicles ......................................................................................................................5591.2.3 Roadways and Lanes..............................................................................................................5591.2.4 Clearance Limit .......................................................................................................................5601.2.5 Widening of Roads at Bends...................................................................................................5611.2.6 Longitudinal Slope...................................................................................................................5611.2.7 Level Crossings.......................................................................................................................5621.2.8 Pavement................................................................................................................................5621.2.9 Signs .......................................................................................................................................5631.3 Car Parks............................................................................................................................................5641.3.1 General ...................................................................................................................................564
  • 19. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-xviii-1.3.2 Size and Location ...................................................................................................................5641.4 Railways .............................................................................................................................................5671.5 Heliports..............................................................................................................................................5671.6 Tunnels ...............................................................................................................................................5671.6.1 General ...................................................................................................................................5671.6.2 Principle of Planning and Design............................................................................................5671.6.3 Depth of Immersion ................................................................................................................5681.6.4 Structure and Length of Immersed Tunnel Elements .............................................................5681.6.5 Ventilation Towers ..................................................................................................................5681.6.6 Access Roads.........................................................................................................................5691.6.7 Calculation of Stability of Immersed Tunnel Section .............................................................. 5691.6.8 Design of Immersed Tunnel Elements....................................................................................5691.6.9 Joints ...................................................................................................................................... 5701.6.10 Control and Operation Facilities .............................................................................................5701.7 Bridges................................................................................................................................................5701.7.1 General ...................................................................................................................................5701.7.2 Design Requirements .............................................................................................................5701.7.3 Structural Durability ................................................................................................................5711.7.4 Fender System .......................................................................................................................571Chapter 2 Cargo Sorting Facilities ...........................................................................................................................5732.1 General ...............................................................................................................................................5732.2 Cargo Sorting Areas .........................................................................................................................5732.3 Quay Sheds .......................................................................................................................................5732.4 Cargo Handling Equipment .............................................................................................................5732.4.1 General ...................................................................................................................................5732.4.2 Oil Handling Equipment..........................................................................................................5742.4.3 Operation and Maintenance of Cargo Handling Equipment ................................................... 5742.5 Timber Sorting Areas........................................................................................................................5742.6 Sorting Facilities for Marine Products ............................................................................................5752.7 Sorting Facilities for Hazardous Cargo.......................................................................................... 575Chapter 3 Storage Facilities.......................................................................................................................................5763.1 General ...............................................................................................................................................5763.2 Yards for Dangerous Cargo and Oil Storage Facilities...............................................................5763.3 Other Storage Facilities....................................................................................................................576Chapter 4 Facilities for Ship Services .....................................................................................................................5774.1 General ...............................................................................................................................................5774.2 Water Supply Facilities.....................................................................................................................577Chapter 5 Facilities for Passenger...........................................................................................................................5785.1 Facilities for Passenger Boarding...................................................................................................5785.1.1 General ...................................................................................................................................5785.1.2 Structural Types...................................................................................................................... 5785.1.3 Design of Facilities for Passenger Boarding...........................................................................5785.1.4 Ancillary Facilities ...................................................................................................................5785.2 Passenger Building...........................................................................................................................5795.2.1 General ...................................................................................................................................5795.2.2 Design of Passenger Buildings...............................................................................................5795.2.3 Ancillary Facilities ...................................................................................................................579Part X Special Purpose WharvesChapter 1 Container Terminals ................................................................................................................................. 5811.1 Principle of Design............................................................................................................................ 5811.2 Design of Mooring Facilities ............................................................................................................5821.2.1 Length and Water Depth of Berths .........................................................................................5821.2.2 Mooring Equipment................................................................................................................. 5821.2.3 Fender System .......................................................................................................................5831.3 Design of Land Facilities..................................................................................................................5831.3.1 Apron ...................................................................................................................................... 5831.3.2 Container Cranes....................................................................................................................5831.3.3 Container Yard........................................................................................................................5831.3.4 Container Freight Station........................................................................................................5831.3.5 Maintenance Shop..................................................................................................................583
  • 20. CONTENTS-xix-1.3.6 Administration Building............................................................................................................5831.3.7 Gates.......................................................................................................................................5831.3.8 Ancillary Facilities....................................................................................................................583Chapter 2 Ferry Terminals ..........................................................................................................................................5842.1 Principle of Design ............................................................................................................................5842.2 Design of Mooring Facilities.............................................................................................................5852.2.1 Length and Water Depth of Berths..........................................................................................5852.2.2 Mooring Equipment.................................................................................................................5852.2.3 Fender System........................................................................................................................5862.2.4 Protection Works against Scouring.........................................................................................5862.3 Design of Vehicle Ramp...................................................................................................................5862.3.1 Width, Length, Gradient, and Radius of Curvature .................................................................5862.3.2 Ancillary Facilities and Signs...................................................................................................5862.3.3 Design of Moving Parts...........................................................................................................5862.4 Facilities for Passenger Boarding...................................................................................................5862.4.1 Width, Length, Gradient, and Ancillary Facilities.....................................................................5872.4.2 Design of Moving Parts...........................................................................................................5872.5 Design of Other Facilities.................................................................................................................5872.5.1 Roads......................................................................................................................................5872.5.2 Passageways..........................................................................................................................5872.5.3 Car Parks ................................................................................................................................5872.5.4 Passenger Terminals ..............................................................................................................5882.5.5 Safety Equipment....................................................................................................................588Part XI MarinasChapter 1 Introduction..................................................................................................................................................589Chapter 2 Main Dimensions of Target Boats ........................................................................................................590Chapter 3 Navigation Channels and Basins..........................................................................................................5913.1 General................................................................................................................................................5913.2 Navigation Channels.........................................................................................................................5913.3 Mooring Basins ..................................................................................................................................591Chapter 4 Protective Facilities ...................................................................................................................................592Chapter 5 Mooring Facilities.......................................................................................................................................5935.1 General................................................................................................................................................5935.2 Design Conditions for Mooring Facilities .......................................................................................5935.3 Floating Piers .....................................................................................................................................5955.3.1 General ...................................................................................................................................5955.3.2 Structure..................................................................................................................................5955.3.3 Examination of Safety .............................................................................................................5955.3.4 Structural Design.....................................................................................................................5965.3.5 Mooring Method ......................................................................................................................5965.3.6 Access Bridges .......................................................................................................................5965.4 Ancillary Facilities..............................................................................................................................5975.5 Lifting / Lowering Frame Facilities ..................................................................................................597Chapter 6 Facilities for Ship Services......................................................................................................................5986.1 General................................................................................................................................................5986.2 Land Storage Facilities .....................................................................................................................598Chapter 7 Land Traffic Facilities................................................................................................................................599INDEX
  • 21. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-xx-
  • 22. Part I General
  • 23. PART I GENERAL-1-Part I GeneralChapter 1 General Rules1.1 Scope of ApplicationThe Ministerial Ordinance stipulating the Technical Standards for Port and Harbour Facilities(Ministry of Transport Ordinance No. 30, 1974; hereafter referred to simply as the Ministerial Ordinance)and the Notification stipulating the Details of Technical Standards for Port and Harbour Facilities(Ministry of Transport Notification No. 181, 1999; hereafter referred to simply as the Notification), both ofwhich have been issued in line with Article 56-2 of the “Port and Harbour Law”, shall be applied to theconstruction, improvement, and maintenance of port and harbor facilities.[Commentary](1) The Ministerial Ordinance and the Notification (hereafter collectively referred to as the Technical Standards)apply not to the port and harbor facilities stipulated in Article 2 of the “Port and Harbour Law”, but rather tothe port and harbor facilities stipulated in Article 19 of the Port and Harbour Law Enforcement Order.Accordingly the Technical Standards also apply to facilities like navigation channels, basins, protectivefacilities and mooring facilities of the marinas and privately owned ports, which are found in outside of thelegally designated port areas.(2) Since the Technical Standards covers a wide rage of facilities, there will be cases where the items shown in theTechnical Standards may be inadequate for dealing with planning, designing, constructing, maintaining orrepairing of a particular individual structure of a port or harbor. There is also possibility that new items may beadded in the future in line with technical developments or innovations. With regard to matters for which thereare no stipulations in the Technical Standards, appropriate methods other than those mentioned in the TechnicalStandards may be adopted, after confirming the safety of a structure in consideration using appropriate methodssuch as model tests or trustworthy numerical calculations (following the main items of the Technical Standards).(3) Figure C- 1.1.1 shows the statutory structure of the Technical Standards.Fig. C- 1.1.1 Statutory Structure of the Technical Standards for Port and Harbour Facilities(4) This document is intended to help individuals concerned with correct interpretation of the Technical Standardsand to facilitate right application of the Ministerial Ordinance and the Notification. This document is made up ofthe main items, along with reference sections marked Commentary and Technical Notes, which supplementthe main items. The texts in large letters are the main items that describe the parts of the Notification and thebasic items that must be obeyed, regarding the items related to the Notification. The sections markedCommentary mainly give the background to and the basis for the Notification, etc. The sections markedTechnical Notes provide investigation methods and/or standards that will be of reference value, when executingactual design works, specific examples of structures, and other related materials.(5) Design methods can be broadly classified into the methods that use the safety factors and the methods that usethe indices based on probability theory, according to the way of judging the safety of structures.A safety factor is not an index that represents the degree of safety quantitatively. Rather, it is determinedthrough experience to compensate for the uncertainty in a variety of factors. In this document, the safety factorsindicate values that are considered by experience to be sufficiently safe under standard conditions. Dependingon the conditions, it may be acceptable to lower the values of safety factors, but when doing so it is necessary tomake a decision using prudent judgement based on sound reasoning.In the case that the probability distributions of loads and structure strengths can be adequately approximated,it is possible to use a reliability design method. Unlike the more traditional design methods in which safetyfactors are used, a reliability design method makes it possible to gain a quantitative understanding of thePort and Harbour Law Enforcement Order Port and Harbour Law EnforcementRegulationsThe NotificationPort and Harbour Law[Article 56-2](technical standards forport and harbour facilities)Port and Harbour LawEnforcement Order[Article 19](stipulation of facilities covered)Port and Harbour LawEnforcement Regulations[Article 28](stipulation of facilities excludedfrom coverage)The Technical StandardsThe Ministerial Ordinance
  • 24. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-2-likelihood of the failure of structure in question and then to keep the likelihood below a certain allowable value.With a reliability design method, design is carried out by using the partial safety factors and reliability indices.Formally speaking, the limit state design method can be classified as one form of reliability design method.1.2 DefinitionsThe terms used in the Notification are based on the terminology used in the Ministerial Ordinance; inaddition, the meanings of the following terms as stipulated in the law or notification are cited.(1) Dangerous articles: This term refers to those that are designated in the Notification stipulating the“Types of Hazardous Goods” for the “Port Regulation Law Enforcement Regulations” (Ministryof Transport Notification No. 547, 1979).(2) Datum level for construction work: This is the standard water level used when constructing,improving or maintaining port and harbor facilities, and is equal to the chart datum level (specificallythe chart datum for which the height is determined based on the provisions of Article 9 (8) of the“Law for Hydrographic Activities” (Law No. 102, 1950)). However, in the case of port and harborfacilities in lakes and rivers for which there is little tidal influence, in order to ensure the safe use ofthe port or harbor in question, the datum level for construction work shall be determined whileconsidering the conditions of extremely low water level that may occur during a drought season.[Commentary]In addition to the terms defined above, the meanings of the following terms are listed below.(1) Super-large vessel: A cargo ship with a deadweight tonnage of 100,000 t or more, except in the case of LPGcarriers and LNG carriers, in which case the gross tonnage is 25,000 t or more.(2) Passenger ship: A vessel with a capacity of 13 or more passengers.(3) Pleasure boat: A yacht, motorboat or other vessel used for sport or recreation.1.3 Usage of SI Units[Commentary]In line with the provisions in the “Measurement Law” (Law No. 51, May 20, 1992), with the aim of executing asmooth switchover to SI units, the Ministry of Agriculture, Forestry and Fisheries, the Ministry of Transport and theMinistry of Construction have concluded to use the International System of Units in their public work projectsstarting from April 1999.
  • 25. PART I GENERAL-3-Table C- 1.3.1 Conversion Factors from Conventional Units to SI UnitsNumber Quantity Non-SI units SI units Conversion factor1 Length µ m 1µ = 1µm2 Mass kgf•s2/m kg 1kgf•s2/m = 9.80665kg3 Acceleration Gal m/s2 1Gal = 0.01m/s24Forcekgf N 1kgf = 9.80665N5 dyn N 1dyn = 10µN6 Moment of a force kgf•m N•m 1kgf•m = 9.80665N•m7Pressurekgf/cm2PaN/mm21kgf/cm2= 9.80665 × 104Pa= 9.80665 × 10-2MPa1kgf/cm2= 9.80665 × 10-2N/mm28 mHg Pa 1mHg = 133.322kPa9 Stress kgf/cm2PaN/mm21kgf/cm2= 9.80665 × 104Pa= 9.80665 × 10-2MPa1kgf/cm2= 9.80665 × 10-2N/mm210Work (energy)kgf•m J 1kfg•m = 9.80665J11 erg J 1erg = 100nJ12 PowerPSHPW1PS = 735.499W1HP = 746.101W13 Quantity of heat calJW•s1cal = 4.18605J1cal = 4.18605W•s14Thermalconductivitycal/(h•m•ºC) W/(m•ºC)1cal/(h•m•ºC)= 0.001163W/(m•ºC)15Heat conductioncoefficientcal/(h•m2•ºC) W/(m2•ºC)1cal/(h•m2•ºC)= 0.001163W/(m2•ºC)16Specific heatcapacitycal/(kg•ºC) J/(kg•ºC)1cal/(kg•ºC)= 4.18605J/(kg•ºC)17 Sound pressure level - dB 1phon = 1dB
  • 26. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-4-Chapter 2 Datum Level for Construction Work[Commentary]The datum level for port and harbor construction work is the standard water level that shall form the basisfor the planning, design, and construction of facilities. The chart datum level shall be used as the datumlevel for construction work.[Technical Notes](1) Chart Datum LevelThe chart datum level is set as the level below the mean sea level by the amount equal to or approximatelyequivalent to the sum of the amplitueds of the four major tidal constituents (M2, S2, K1, and O1 tides), which areobtained from the harmonic analysis of tidal observation data. Here M2 is the principal lunar semi-diurnal tide,S2 is the principal solar semi-diurnal tide, K1 is the luni-solar diurnal tide, and O1 is the principal lunar diurnaltide.Note that the heights of rocks or land marks shown on the nautical charts are the elevation above the meansea level, which is the long-term average of the hourly sea surface height at the place in question. (In the casethat the observation period is short, however, corrections for seasonal fluctuations should be made whendetermining the mean sea level.) The difference in height between the chart datum level and the mean sea levelis referred to as Z0.(2) International Marine Chart DatumThe International Hydrographic Organization (IHO) has decided to adopt the Lowest Astronomical Tide (LAT)as the international marine chart datum, and issued a recommendation to this effect to the HydrographicDepartments in various countries throughout the world in June 1997. The LAT is defined as the lowest sea levelthat is assumed to occur under the combination of average weather conditions and generally conceivableastronomical conditions. In actual practice, tide levels for at least 19 years are calculated using harmonicconstants obtained from at least one year’s worth of observations, and then the lowest water level is taken as theLAT.However, in the case of Japan, the chart datum level is obtained using the old method described in (1) above(approximate lowest water level). There will be no switchover to the LAT in the near future in Japan, but it isplanned to meet the IHO recommendation by stating the difference between the LAT and the chart datum levelin tide tables published by the Hydrographic Department of Maritime Safety Agency, Ministry of Land,Infrastructure, and Transport, Japan.
  • 27. PART I GENERAL-5-Chapter 3 MaintenanceIn order to maintain the functions of port and harbor facilities at a satisfactory service level and to preventdeterioration in the safety of such facilities, comprehensive maintenance including inspections,evaluations, repairs, etc. shall be carried out, in line with the specific characteristics of the port or harbor inquestion.[Commentary](1) “Maintenance” refers to a system consisting of a series of linked activities involving the efficient detection ofchanges in the state of serviceability of the facilities and the execution of effective measures such as rationalevaluation, repair, and reinforcement.(2) Port and harbor facilities must generally remain in service for long periods of time, during which the functionsdemanded of the facilities must be maintained. It is thus essential not only to give due consideration wheninitially designing the structures in question, but also to carry out proper maintenance after the facilities havebeen put into service.(3) A whole variety of data concerning maintenance (specifically, inspections, checks, evaluations, repair,reinforcement work, etc.) must be recorded and stored in a standard format. Maintenance data kept in goodsystematic order is the basic information necessary for carrying out appropriate evaluation of the level ofsoundness of the facilities in question, and executing their maintenance and repairs. At the same time themaintenace data is useful when taking measures against the deterioration of the facilities as a whole and wheninvestigating the possibility in the life cycle cost reduction of the facilities.(4) When designing a structure, it is necessary to give due consideration to the system of future maintenance and toselect the types of structures and the materials used so that future maintenance will be easily executed, whilereflecting this aspect in the detailed design.•[Technical Notes](1) The concepts of the terms relating to maintenance are as follows:(2) With regard to the procedure for maintenance, it is a good idea to draw up a maintenance plan for each structurewhile considering factors like the structural form, the tendency to deteriorate and the degree of importance, andthen to implement maintenance work based on this plan.(3) For basic and common matters concerning maintenance, refer to the “Manual for Maintenance and Repair ofPort and Harbor Structures”.MaintenanceInspection / checking:• • • •Activities to investigate the state of a structure, the situationregarding damage and the remaining level of function, along withrelated administrative work: mainly composed of periodic andspecial inspectionsEvaluation: • • • • • • • • • • • • • • • Evaluation of the level of soundness based on the results ofinspection / checking, and judgement of the necessity or otherwiseof repairs etc.Maintenance: • • • • • • • • • • • • •Activities carried out with the aim of holding back the physicaldeterioration of a structure and keeping its function withinacceptable levels.Repair / reinforcement: • • Activities in which a structure that has deteriorated physically and/or functionally is partially reconstructed in order to restore therequired function and/or structure.
  • 28. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-6-
  • 29. Part II Design Conditions
  • 30. PART II DESIGN CONDITIONS-7-Part II Design ConditionsChapter 1 GeneralIn designing port and harbor facilities, the design conditions shall be chosen from the items listed below bytaking into consideration the natural, service and construction conditions, the characteristics of materials,the environmental impacts, and the social requirements for the facilities.(1) Ship dimensions(2) External forces produced by ships(3) Winds and wind pressure(4) Waves and wave force(5) Tide and extraordinary sea levels(6) Currents and current force(7) External forces acting on floating structures and their motions(8) Estuarine hydraulics and littoral drift(9) Subsoil(10) Earthquakes and seismic force(11) Liquefaction(12) Earth pressure and water pressure(13) Deadweight and surcharge(14) Coefficient of friction(15) Other necessary design conditions[Commentary]The design conditions should be determined carefully, because they exercise great influence upon the safety,functions, and construction cost of the facilities. The design conditions listed above are just those that have a largeinfluence on port and harbor facilities. They are generally determined according to the results of surveys and tests.Thus, the design conditions should be precisely determined upon full understanding of the methods and results ofsuch investigations and tests. In the case of temporary structures, the design conditions may be determined whileconsidering also the length of service life.[Technical Notes](1) In designing port and harbor facilities, the following matters should be taken into consideration.(a) Functions of the facilitiesSince facilities often have multiple functions, care should be exercised so that all functions of the facilities willbe exploited fully.(b) Importance of the facilitiesThe degree of importance of the facilities should be considered in order to design the facilities by takingappropriate account of safety and broad economic implications. The design criteria influenced by importanceof facilities are those of environmental conditions, design seismic coefficient, lifetime, loads, safety factor,etc. In determining the degree of importance of the facilities, the following criteria should be taken intoconsideration.• Influence upon human lives and property if the facilities are damaged.• Impact on society and its economy if the facilities are damaged.• Influence upon other facilities if the facilities are damaged.• Replaceability of the facilities.(c) LifetimeThe length of lifetime should be taken into account in determining the structure and materials of the facilitiesand also in determining the necessity for and extent of the improvement of the existing facilities. Lifetime ofthe facilities should be determined by examinig the following:• Operational function of the facilitiesThe number of years until the facilities can no longer be usable due to the occurrence of problems in termsof the function of the facilities, for example the water depth of a mooring basin becoming insufficient owingto the increase in vessel size.• Economic viewpoint of the facilitiesThe number of years until the facilities become economically uncompetitive with other newer facilities(unless some kind of improvements are carried out).
  • 31. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-8-• Social function of the facilitiesThe number of years until the functions of the facilities that constituted the original purpose becomeunnecessary or until different functions are called for the facilities due to new port planning etc.• Physical property of the facilitiesThe number of years until it is no longer possible to maintain the strength of materials composing thestructures at the specified level due to processes such as corrosion or weathering of these materials.(d) Encounter probabilityThe encounter probability is intimately linked with the lifetime length. The encounter probability E1 isobtained using equation (1.1.1) 1)(1.1.1)whereL1: lifetime length: return period(e) Environmental conditionsNot only the wave, seismic, topographical and soil conditions, which have direct influences on the design ofthe facilities, but also the water quality, bottom material, animal and plant life, atmospheric conditions andrising sea level due to global warming should be taken into consideration.(f) MaterialsIt is necessary to consider the physical external forces, deterioration, lifetime, structural type, constructionworks, cost, and influence on the environment and landscape when selecting the materials. It is most importantto ensure the reguired quality. In recent years, in addition to more traditional materials, new materials such asstainless steels, titanium and new rubbers, and recycled materials such as slag, coal ash and dredged sedimenthave begun to be used.(g) Construction methodIn order to carry out design rationally, it is necessary to give sufficient consideration to the constructionmethod.(h) Work accuracyIt is necessary to carry out design considering the accuracy of construction works that can be maintained inactual projects.(i) Construction periodIn the case that the construction period is stipulated, it is necessary to give consideration both to the design andthe construction method, in order that it will be possible to complete construction work within the stipulatedperiod. The construction period is generally determined by things like the availability of the materials, theconstruction equipment, the degree of difficulty of construction, the opening date and the natural conditions.(j) Construction costs etc.Construction costs consist of the initial investment costs and maintenance costs. All of these costs must beconsidered in design and construction. When doing this, it is necessary to consider the early use of thefacilities and to secure an early return on investment. There is also a design approach that the facilities are putinto service step by step as the construction progresses, while ensuring the safety of service / construction.Note also that the initial investment costs mentioned here include compensation duties.When carrying out design etc., due consideration must be given to things like the structural type and theconstruction method, since the construction costs will depend on these things.[Reference]1) Borgman, L. E.: “Risk criteria”, Proc. ASCE, Vol. 89, No. WW3, 1963, pp.1-35.E1 1 1 1 T1¤–( )L1–=T1
  • 32. PART II DESIGN CONDITIONS-9-Chapter 2 Vessels2.1 Dimensions of Target Vessel (Notification Article 21)The principal dimensions of the target vessel shall be set using the following method:(1) In the case that the target vessel can be identified, use the principal dimensions of that vessel.(2) In the case that the target vessel cannot be identified, use appropriate principal dimensions determinedby statistical methods.[Technical Notes](1) Article 1, Clause 2 of the Ministerial Ordinance stipulates that the “target vessel” is the vessel that has thelargest gross tonnage out of those that are expected to use the port or harbor facilities in question. Accordingly,in the case that the target vessel can be identified, the principal dimensions of this vessel should be used.(2) In the case that the target vessel cannot be identified in advance, such as in the case of port and harbor facilitiesfor public use, the principal dimensions of the target vessel may be determined by referring to Table T- 2.1.1. Inthis table, the tonnages (usually either gross or deadweight tonnage) are used as representative indicators.(3) Table T- 2.1.1 lists the “principal dimensions of vessels for the case that the target vessel cannot be identified”by tonnage level. These values have been obtained through methods such as statistical analysis 1),2), and theymainly represent the 75% cover ratio values for each tonnage of vessels. Accordingly, for any given tonnage,there will be some vessels that have principal dimensions that exceed the values in the table. There will also bevessels that have a tonnage greater than that of the target vessel listed in the table, but still have principaldimensions smaller than those of the target vessel.(4) Table T- 2.1.1 has been obtained using the data from “Lloyd’s Maritime Information June ’95” and “NihonSenpaku Meisaisho” (“Detailed List of Japanese Vessels”; 1995 edition). The definitions of principaldimensions in the table are shown in Fig. T- 2.1.1.(5) Since the principal dimensions of long distance ferries that sail over 300km tend to have different characteristicsfrom those of short-to-medium distance ferries, the principal dimensions are listed separately for “long distanceferries” and “short-to-medium distance ferries.”(6) Since the principal dimensions of Japanese passenger ships tend to have different characteristics from those offoreign passenger ships, the principal dimensions are listed separately for “Japanese passenger ships” and“foreign passenger ships”.(7) The mast height varies considerably even for vessels of the same type with the same tonnage, and so whendesigning facilities like bridges that pass over navigation routes, it is necessary to carry out a survey on the mastheights of the target vessels.(8) In the case that the target vessel is known to be a small cargo ship but it is not possible to identify precisely thedemensions of the ship in advance, the principal dimensions of “small cargo ships” can be obtained by referringto Table T- 2.1.2. The values in Table T- 2.1.2 have been obtained using the same kind of procedure as those inTable T- 2.1.1, but in the case of such small vessels there are large variations in the principal dimensions and soparticular care should be exercised when using Table T- 2.1.2.(9) TonnageThe definitions of the various types of tonnage are as follows:(a) Gross tonnageThe measurement tonnage of sealed compartments of a vessel, as stipulated in the “Law Concerning theMeasurement of the Tonnage of Ships”. The “gross tonnage” is used as an indicator that represents the sizeof a vessel in Japan’s maritime systems. Note however that there is also the “international gross tonnage”,which, in line with the provisions in treaties etc., is also used as an indicator that represents the size of a vessel,but mainly for vessels that make international sailings. The values of the “gross tonnage” and the“international gross tonnage” can differ from one another; the relationship between the two is stipulated inArticle 35 of the “Enforcement Regulations for the Law Concerning the Measurement of the Tonnage ofShips” (Ministerial Ordinance No. 47, 1981).(b) Deadweight tonnageThe maximum weight, expressed in tons, of cargo that can be loaded onto a vessel.(c) Displacement tonnageThe amount of water, expressed in tons, displaced by a vessel when it is floating at rest.(10) For the sake of consistency, equation (2.1.1) shows the relationship between the deadweight tonnage (DWT) andthe gross tonnage (GT) for the types of vessels that use the deadweight tonnage as the representative indicator 1).For each type of vessels, the equation may be applied if the tonnage is within the range shown in Table T- 2.1.1.
  • 33. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-10-Cargo ships: GT = 0.541DWTContainer ships: GT = 0.880DWTOil tankers: GT = 0.553DWTRoll-on/roll-off vessels: GT = 0.808DWTwhereGT : gross tonnageDWT : deadweight tonnage(11) Tables T-2.1.3 to T-2.1.6 list the frequency distribution of the principal dimensions of general cargo ships, bulkcargo carriers, container ships, and oil tankers, which were analyzed by the Systems Laboratory of Port andHarbour Research Institute (PHRI) using the data from “Lloyd’s Maritime Informations Services (June ’98)”.Fig. T- 2.1.1 Definitions of Principal Dimensions of VesselTable T- 2.1.1 Principal Dimensions of Vessels for the Case That the Target Vessel Cannot Be Identified1. Cargo ships2. Container shipsDeadweight tonnage (DWT) Length overall (L) Molded breadth (B) Full load draft (d)1,000 ton2,0003,0005,00010,00012,00018,00030,00040,00055,00070,00090,000100,000150,00067 m839410913714416118520021823324925628610.9 m13.114.616.819.921.023.627.529.932.332.338.139.344.33.9 m4.95.66.58.28.69.611.011.812.913.714.715.116.9Deadweight tonnage (DWT) Length overall (L) Molded breadth (B) Full load draft (d)30,000 ton40,00050,00060,000218 m24426628630.2 m32.332.336.511.1 m12.213.013.8(2.1.1)64748FullloaddraftLength overallLoad water lineLength between perpendicularsAfter perpendicular Fore perpendicularMoulded breadthMouldeddepth
  • 34. PART II DESIGN CONDITIONS-11-3. Ferries3-A Short-to-medium distance ferries (sailing distance less than 300km)3-B Long distance ferries (sailing distance 300km or more)4. Roll-on/roll-off vessels5. Passenger ships5-A Japanese passenger ships5-B Foreign passenger ships6. Pure car carriersGross tonnage (GT) Length overall (L) Molded breadth (B) Full load draft (d)400 ton7001,0002,5005,00010,00050 m637210413614811.8 m13.514.718.321.623.03.0 m3.43.74.65.35.7Gross tonnage (GT) Length overall (L) Molded breadth (B) Full load draft (d)6,000 ton10,00013,00016,00020,00023,000142 m16718519219220022.3 m25.227.328.228.228.26.0 m6.46.86.86.87.2Deadweight tonnage (DWT) Length overall (L) Molded breadth (B) Full load draft (d)400 ton1,5002,5004,0006,00010,00075 m9711513415418213.6 m16.418.520.722.925.911.1 m4.75.56.37.07.4Gross tonnage (GT) Length overall (L) Molded breadth (B) Full load draft (d)2,000 ton4,0007,00010,00020,00030,00083 m10713014718821715.6 m18.521.223.227.530.44.0 m4.95.76.66.66.6Gross tonnage (GT) Length overall (L) Molded breadth (B) Full load draft (d)20,000 ton30,00050,00070,000180 m20724827825.7 m28.432.335.28.0 m8.08.08.0Gross tonnage (GT) Length overall (L) Molded breadth (B) Full load draft (d)500 ton1,5003,0005,00012,00018,00025,00070 m9411413016518420011.8 m15.718.821.527.030.032.33.8 m5.05.86.68.08.89.5
  • 35. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-12-7. Oil tankersTable T- 2.1.2 Principal Dimensions of Small Cargo ShipsTable T-2.1.3 Frequency Distributions of Principal Dimensions of General Cargo Ships(a) DWT - Length overall(b) DWT - Breadth(c) DWT - Full load draftDeadweight tonnage (DWT) Length overall (L) Molded breadth (B) Full load draft (d)1,000 ton2,0003,0005,00010,00015,00020,00030,00050,00070,00090,00061 m768710212714415818021123525410.2 m12.614.316.820.823.625.829.232.338.041.14.0 m4.95.56.47.98.99.610.912.613.915.0Deadweight tonnage (DWT) Length overall (L) Molded breadth (B) Full load draft (d)500 ton70051 m579.0 m9.53.3 m3.4L*@
  • 36. PART II DESIGN CONDITIONS-13-Table T-2.1.4 Frequency Distributions of Principal Dimensions of Bulk Cargo Carriers(a) DWT - Length overall(b) DWT - Breadth(c) DWT - Full load draftL*@
  • 37. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-14-Table T-2.1.5 Frequency Distributions of Principal Dimensions of Container Ships(a) DWT - Length overall(b) DWT - Breadth(c) DWT - Full load draft(d) DWT - TEUL*dunknownunknown
  • 38. PART II DESIGN CONDITIONS-15-Table T-2.1.6 Frequency Distributions of Principal Dimensions of Oil Tankers(a) DWT - Length overall(b) DWT - Breadth(c) DWT - Full load draftL*@
  • 39. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-16-2.2 External Forces Generated by Vessels2.2.1 GeneralThe external forces acting on the mooring facilities when a vessel is berthing or moored shall bedetermined using an appropriate method, considering the dimensions of the target vessel, the berthingmethod and the berthing velocity, the structure of the mooring facilities, the mooring method and theproperties of the mooring system, along with the influence of things like the winds, waves and tidalcurrents.[Commentary](1) The following loads acting on mooring facilities should be considered when a vessel is berthing or moored:a) Loads caused by berthing of a vesselb) Loads caused by motions of a moored vesselWhen designing mooring facilities, the berthing force must be considered first. Then the impact forces andtractive forces on the mooring facilities due to the motions of the moored vessel, which are caused by the waveforce, wind force and current force, should be considered. In particular, for the cases of the mooring facilities inthe ports and harbors that face out onto the open sea with long-period waves expected to come in, of thoseinstalled in the open sea or harbor entrances such as offshore terminals, and of those in the harbors where vesselsseek refuge during storms, the influence of the wave force acting on a vessel is large and so due considerationmust be given to the wave force.(2) As a general rule, the berthing forces acting on the mooring facilities should be calculated based on the berthingenergy of the vessel and using the load-deflection characteristics of the fenders.(3) As a general rule, the tractive forces and impact forces generated by the motions of a moored vessel should beobtained by carrying out a numerical simulation of vessel motions taking into account the wave force acting onthe vessel, the wind force, the current force, and the load-deflection characteristics of the mooring system.2.2.2 Berthing[1] Berthing Energy (Notification Article 22, Clause 1)It shall be standard to calculate the external force generated by berthing of a vessel with the followingequation:(2.2.1)In this equation, , , V, , , , and represent the following:: berthing energy of vessel (kJ = kN•m): mass of vessel (t)V: berthing velocity of vessel (m/s): eccentricity factor: virtual mass factor: softness factor (standard value is 1.0): berth configuration factor (standard value is 1.0)[Commentary]In addition to the kinetic energy method mentioned above, there are also other methods of estimating the berthingenergy of a vessel: for example, statistical methods, methods using hydraulic model experiments, and methods usingfluid dynamics models 3). However, with these alternative methods, the data necessary for design are insufficient andthe values of the various constants used in the calculations may not be sufficiently well known. Thus, the kineticenergy method is generally used.[Technical Notes](1) If it is assumed that a berthing vessel moves only in the abeam direction, then the kinetic energy is equal to. However, when a vessel is berthing at a dolphin, a quaywall, or a berthing beam equipped withfenders, the energy absorbed by the fenders (i.e., the berthing energy of the vessel) will becomeconsidering the various influencing factors, where .(2) The vessel mass is taken to be the displacement tonnage (DT) of the target vessel. In the case that the targetvessel cannot be identified, equation (2.2.2) 1) may be used to give the relationship between the deadweighttonnage (DWT) or the gross tonnage (GT) and the displacement tonnage (DT).EfMsV22-------------è øæ öCeCmCsCc=Ef Ms Ce Cm Cs CcEfMsCeCmCsCcEsMsV2( ) 2¤Ef Es f´f Ce Cm´ Cs´ Cc´=Ms
  • 40. PART II DESIGN CONDITIONS-17-Cargo ships (less than 10,000DWT): log (DT) = 0.550 + 0.899 log (DWT)Cargo ships (10,000DWT or more): log (DT) = 0.511 + 0.913 log (DWT)Container ships: log (DT) = 0.365 + 0.953 log (DWT)Ferries (long distance): log (DT) = 1.388 + 0.683 log (GT)Ferries (short-to-medium distance): log (DT) = 0.506 + 0.904 log (GT)Roll-on/roll-off vessels: log (DT) = 0.657 + 0.909 log (DWT)Passenger ships (Japanese): log (DT) = 0.026 + 0.981 log (GT)Passenger ships (foreign): log (DT) = 0.341 + 0.891 log (GT)Car carriers: log (DT) = 1.915 + 0.588 log (GT)Oil tankers: log (DT) = 0.332 + 0.956 log (DWT)whereDT: displacement tonnage (amount of water, in tons, displaced by the vessel when fully loaded)GT: gross tonnageDWT: deadweight tonnage(3) The softness factor represents the ratio of the remaining amount of the berthing energy after energyabsorption due to deformation of the shell plating of the vessel to the initial berthing energy. It is generallyassumed that no energy is absorbed in this way and so the value of is often given as 1.0.(4) When a vessel berths, the mass of water between the vessel and the mooring facilities resists to move out andacts just as if a cushion is placed in this space. The energy that must be absorbed by the fenders is thus reduced.This effect is considered when determining the berth configuration factor . It is thought that the effectdepends on things like the berthing angle, the shape of the vessel’s shell plating, the under-keel clearance, andthe berthing velocity, but little research has been carried out to determine it.[2] Berthing VelocityThe berthing velocity of a vessel shall be determined based on the measurement in situ or past data ofsimilar measurements, considering the type of the target vessel, the extent to which the vessel is loaded, theposition and structure of the mooring facilities, weather and oceanographic conditions, and the availabilityor absence of tugboats and their sizes.[Technical Notes](1) Observing the way in which large cargo ships and large oil tankers make berthing, one notices that such vesselscome to a temporary standstill, lined up parallel to the quaywall at a certain distance away from it. They are thengently pushed by several tugboats until they come into contact with the quay. When there is a strong windblowing toward the quay, such vessels may berth while actually being pulled outwards by the tugboats. Whensuch a berthing method is adopted, it is common to set the berthing velocity to 10 ~ 15 cm/s based on past designexamples.(2) Special vessels such as ferries, roll-on/roll-off vessels, and small cargo ships berth under their own powerwithout assistance of tugboats. If there is a ramp at the bow or stern of such a vessel, the vessel may line upperpendicular to the quay. In these cases, a berthing method different from that for larger vessels described in (1)may be used. It is thus necessary to determine berthing velocities carefully based on actualy measured values,paying attention to the type of berthing method employed by the target vessel.(3) Figure T- 2.2.1 shows the relationship between the vessel handling conditions and berthing velocity by vesselsize 4); it has been prepared based on the data collected through experience. This figure shows that the larger thevessel, the lower the berthing velocity becomes; moreover, the berthing velocity must be set high if the mooringfacilities is not sheltered by breakwaters etc.(4) According to the results of surveys on berthing velocity 5),6), the berthing velocity is usually less than 10 cm/s forgeneral cargo ships, but there are a few cases where it is over 10 cm/s (see Fig. T- 2.2.2). The berthing velocityonly occasionally exceeds 10 cm/s for large oil tankers that use offshore terminals (see Fig. T- 2.2.3). Even forferries which berth under their own power, the majority berth at the velocity of less than 10 cm/s. Nevertheless,there are a few cases in which the berthing velocity is over 15 cm/s and so due care must be taken whendesigning ferry quays (see Fig. T- 2.2.4). It was also clear from the above-mentioned survey results that thedegree to which a vessel is loaded up has a considerable influence on the berthing velocity. In other words, if avessel is fully loaded, meaning that the under-keel clearance is small, then the berthing velocity tends to belower, whereas if it is lightly loaded, meaning that the under-keel clearance is large, then the berthing velocitytends to be higher.64444744448(2.2.2)CsCsCc
  • 41. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-18-Fig. T- 2.2.1 Relationship between Vessel Handling Conditions and Berthing Velocity by Vessel Size 4)Fig. T- 2.2.2 Berthing Velocity and Displacement Tonnage for General Cargo Ships 5)Fig. T- 2.2.3 Berthing Velocity and Displacement Tonnage for Large Oil Tankers 6)Fig. T- 2.2.4 Berthing Velocity and Displacement Tonnage for Longitudinal Berthing of Ferries 5)DifficultexposedGood berthingexposedEasy berthingexposedDifficult berthingshelteredGood berthingshelteredDifficultyofhandlingvessel/mooringfacilitiesbeingshelterdornot Berthing velocity (cm/s)Open type quayWall type quay (sheet pile, gravity types)Berthingvelocity(cm/s)Displacement tonnage ,6 (tons)Displacement tonnage ,6 (10,000 tons)Berthingvelocity(cm/s)Displacement tonnage ,6 (tons)Berthingvelocity(cm/s)Stern berthingBow berthing
  • 42. PART II DESIGN CONDITIONS-19-According to the survey by Moriya et al., the average berthing velocities for cargo ships, container ships, andpure car carriers are as listed in Table T- 2.2.1. The relationship between the deadweight tonnage and berthingvelocity is shown in Fig. T- 2.2.5. This survey also shows that the larger the vessel, the lower the berthingvelocity tends to be. The highest berthing velocities observed were about 15 cm/s for vessels under 10,000 DWTand about 10 cm/s for vessels of 10,000 DWT or over.Table T- 2.2.1 Deadweight Tonnage and Average Berthing Velocity(5) Figure T- 2.2.6 shows a berthing velocity frequency distribution obtained from actual measurement records atoffshore terminals used by large oil tankers of around 200,000 DWT. It can be seen that the highest measuredberthing velocity was 13 cm/s. If the data are assumed to follow a Weibull distribution, then the probability ofthe berthing velocity below the value 13 cm/s would be 99.6%. The mean µ is 4.41 cm/s and the standarddeviation s is 2.08 cm/s. Application of the Weibull distribution yields the probability density function asexpressed in equation (2.2.3):(2.2.3)whereV: berthing velocity (cm/s)From this equation, the probability of the berthing velocity exceeding 14.5 cm/s becomes 1/1000. The offshoreterminals where the berthing velocity measurements were taken had a design berthing velocity of either 15 cm/sor 20 cm/s 7).(6) Small vessels such as small cargo ships and fishing boats come to berths by controlling their positions undertheir own power without assistance of tugboats. Consequently, the berthing velocity is generally higher than thatfor larger vessels, and in some cases it can even exceed 30 cm/s. For small vessels in particular, it is necessary tocarefully determine the berthing velocity based on actually measured values etc.(7) In cases where cautious berthing methods such as those described in (1) are not used, or in the case of berthingof small or medium-sized vessels under influence of currents, it is necessary to determine the berthing velocitybased on actual measurement data etc., considering the ship drift velocity by currents.(8) When designing mooring facilities that may be used by fishing boats, it is recommended to carry out designworks based on the design standards for fishing port facilities and actual states of usage.Deadweight tonnage(DWT)Berthing velocity (cm/s)Cargo ships Container ships Pure car carriers All vessels1,000 class5,000 class10,000 class15,000 class30,000 class50,000 class8.16.75.04.53.93.5-7.87.24.94.13.4--4.64.74.4-8.17.25.34.64.13.4All vessels 5.2 5.0 4.6 5.0Dead weight tonnage (DWT)Cargo shipsContainer shipsPure car carriersV(cm/s)Poisson distribution m = 3Poisson distribution m = 4Weibull distributionNormal distributionV (cm/s)N=738NFig. T- 2.2.5 Relationship between DeadweightTonnage and Berthing VelocityFig. T- 2.2.6 Frequency Distribution ofBerthing Velocity 10)f V( )f V( )V0.8------- V1.25–( )exp=
  • 43. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-20-[3] Eccentricity Factor (Notification Article 22, Clause 2)The eccentricity factor shall be calculated by the following:(2.2.4)where l and r represent the following:l: distance from the point where the vessel touches the mooring facilities to the center of gravity ofthe vessel as measured along the face line of the mooring facilities (m)r: radius of gyration around the vertical axis passing through the center of gravity of the vessel (m)[Technical Notes](1) When a vessel is in the middle of berthing operation, it is not aligned perfectly along the face line of the berth.This means that after it comes into contact with the mooring facilities (fenders), it starts yawing and rolling. Thisresults in some of the vessel’s kinetic energy being used up. The amount of energy used up by rolling is smallcompared with that by yawing and can be ignored. Equation (2.2.4) thus only considers the amount of energyused up by yawing.(2) The radious of gyration r relative to Lpp is a function of the block coefficient of the vessel and can beobtained from Fig. T- 2.2.7 8). Alternatively, one may use the linear approximation shown in equation (2.2.5) .(2.2.5)wherer: radius of gyration; this is related to the moment of inertia around the vertical axis of the vessel bythe relationship: length between perpendiculars (m): block coefficient; = /( Bd) ( : Volume of water displaced by the vessel (m3), B: mouldedbreadth (m), d: draft (m))(3) As sketched in Fig. T- 2.2.8, when a vessel comes into contact with the fenders F1 and F2 with the point of thevessel closest to the quaywall being the point P, the distance l from the point of contact to the center of gravity ofthe vessel as measured parallel to the mooring facilities is given by equation (2.2.6) or (2.2.7); l is taken to bewhen k < 0.5 and when k > 0.5. When k = 0.5, l is taken as whichever of or that gives the highervalue of in equation (2.2.4).(2.2.6)(2.2.7)Ce11lr--è øæ ö2+--------------------=Cbr 0.19Cb 0.11+( )Lpp=IzIz Msr2=LppCb Cb Ñ Lpp ÑL1 L2 L1 L2CeθQGBBAAPF2F1eLppcosθkeLppcosθLppαLppRadiusofgyrationinthelongitudinaldirection(r)Lengthbetweenperpendiculars(Lpp)Block coefficient CbFig. T- 2.2.7 Relationship between the Radius of Gyrationaround the Vertical Axis and the BlockCoefficient (Myers, 1969) 7)Fig. T- 2.2.8 Vessel BerthingL2 0.5a e 1 k–( )+ Lpp qcos=L1 0.5a ek–( )Lpp qcos=
  • 44. PART II DESIGN CONDITIONS-21-where: distance from the point of contact to the center of gravity of the vessel as measured parallel to themooring facilities when the vessel makes contact with fender F1: distance from the point of contact to the center of gravity of the vessel as measured parallel to themooring facilities when the vessel makes contact with fender F2q: berthing angle (the value of q is set as a design condition; it is usually set somewhere in the range0 ~ 10º)e: ratio of the distance between the fenders, as measured in the longitudinal direction of the vessel, to thelength between perpendicularsa: ratio of the length of the parallel side of the vessel at the height of the point of contact with the fender tothe length between perpendiculars; this varies according to factors like the type of vessel, and the blockcoefficient etc., but is generally in the range 1/3 ~ 1/2.k: parameter that represents the relative location of the point where the vessel comes closest to the mooringfacilities between the fenders F1 and F2 ; k varies between 0 and 1, but it is generally taken at k = 0.5.[4] Virtual Mass Factor (Notification Article 22, Clause 3)It shall be standard to calculate the virtual mass factor using the following equations:where Cb,Ñ, Lpp, B, and d represent the following:: block coefficient: volume of water displaced by the vessel (m3): length between perpendiculars (m)B: moulded breadth (m)d: full load draft (m)[Technical Notes](1) When a vessel berths, the vessel (which has mass ) and the water mass surrounding the vessel (which hasmass ) both decelerate. Accordingly, the inertial force corresponding to the water mass is added to that of thevessel itself. The virtual coefficient is thus defined as in equation (2.2.9).(2.2.9)where: virtual mass factor: mass of vessel (t): mass of the water surrounding the vessel (added mass) (t)Ueda 8) proposed equation (2.2.8) based on the results of model experiments and field observations. The secondterm in equation (2.2.8) corresponds to in equation (2.2.9).(2) As a general rule, the actual values of the target vessel are used for the length between perpendiculars ( ), themoulded breadth (B), and the full load draft (d). But when one of the standard ship sizes is used, one may use theprincipal dimensions given in 2.1 Dimensions of the Target Vessel. Regression equations have been proposedfor the relationships between the deadweight tonnage, the moulded breadth and the full load draft 1). It is alsopossible to use equations (2.2.10), which give the relationship between the deadweight tonnage (DWT) or thegross tonnage (GT) and the length between perpendiculars for different types of vessel 1).Cargo ships (less than 10,000 DWT): log (Lpp) = 0.867 + 0.310 log (DWT)Cargo ships (10,000 DWT or more): log (Lpp) = 0.964 + 0.285 log (DWT)Container ships: log (Lpp) = 0.516 + 0.401 log (DWT)Ferries (long distance, 13,000 GT or less): log (Lpp) = log (94.6 + 0.00596GT)Ferries (short-to-medium distance, 6,000 t or less): log (Lpp) = 0.613 + 0.401 log (GT)Roll-on/roll-off vessels: log (Lpp) = 0.840 + 0.349 log (DWT)Passenger ships (Japanese): log (Lpp) = 0.679 + 0.359 log (GT)Passenger ships (foreign): log (Lpp) = 0.787 + 0.330 log (GT)Car carriers: log (Lpp) = 1.046 + 0.280 log (GT)Oil tankers: log (Lpp) = 0.793 + 0.322 log (DWT)L1L2Cm 1p2Cb---------+dB---´=64748(2.2.8)CbÑLppBd---------------=CbÑLppMsMwCmMs Mw+Ms---------------------=CmMsMwMw Ms¤Lpp64444744448(2.2.10)
  • 45. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-22-(3) The volume of water displaced by the vessel is determined by dividing the displacement tonnage DT by thedensity of seawater (1.03 t/m3)2.2.3 Moored Vessels[1] Motions of Moored Vessel (Notification Article 23)As a general rule, the external forces generated by the motions of a moored vessel shall be calculated bycarrying out a numerical simulation of vessel motions, with the wave force acting on the vessel, the windforce, the current force due to water currents, etc. being set appropriately.[Commentary](1) Vessels moored at mooring facilities situated in the open sea or near to harbor entrances, or at mooring facilitiesinside harbors for which long-period waves are expected to come in, along with vessels moored during stormyweather, are liable to be moved under the influence of loads due to waves, winds, currents, etc. In some cases,the kinetic energy due to such motions can exceed the berthing energy. In such cases, it is thus advisable to givefull consideration to the tractive forces and impact forces caused by the motions of vessels when designingbollards and fenders 10).(2) As a general rule, the external forces generated by the motions of a vessel should be obtained by carrying out anumerical simulation of vessel motions, based on the factors such as the wave force acting on the vessel, thewind force, the current force due to currents, and the load-deflection characteristics of the mooring system.[Technical Notes](1) As a general rule, the motions of a moored vessel should be analyzed through numerical simulation, withconsideration given to the random variations of the loads and the nonlinearity of the load-deflectioncharacteristics of the mooring system. However, when such a numerical simulation of vessel motions is notpossible, or when the vessel is moored at a system that is considered to be more-or-less symmetrical, one mayobtain the displacement of and loads on the mooring system either by using frequency response analysis forregular waves or by referring to results of an motion analysis on a floating body moored at a system that hasload-deflection characteristics of bilinear nature 11).(2) The total wave force acting on the hull of a vessel is analyzed by dividing it into the wave exciting force due toincident waves and the radiation force that is generated as the vessel moves. The wave exciting force due toincident waves is the wave force calculated for the case that motions of the vessel are restrained. The radiationforce is the wave force exerted on the hull when the vessel undergoes a motion of unit amplitude for each modeof motions. The radiation force can be expressed as the summation of a term that is proportional to theacceleration of the vessel and a term that is proportional to the velocity. Specifically, the former can be expressedas an added mass divided by acceleration, while the latter can be expressed as a damping coefficient divided byvelocity 12). In addition, a nonlinear fluid dynamic force that is proportional to the square of the wave height actson the vessel (see 8.2 External Forces Acting on Floating Body).(3) For vessels that have a block coefficient of 0.7 ~ 0.8 such as large oil tankers, the ship hull can be representedwith an elliptical cylinder, allowing an approximate evaluation of the wave force 13).(4) For box-shaped vessels such as working craft, the wave force can be obtained by taking the vessel to be either afloating body with a rectangular cross section or a floating body of a rectangular prism.[2] Waves Acting on VesselThe wave force acting on a moored vessel shall be calculated using an appropriate method, considering thetype of vessel and the wave parameters.[Commentary]The wave force acting on a moored vessel is calculated using an appropriate method, for example the strip method,the source distribution technique, the boundary element method, or the finite element method; the most commonmethod used for vessels is the strip method.[Technical Notes](1) Wave Force by the Strip Method 11), 12)(a) Wave force of regular waves acting on the hullThe wave force acting on the hull is taken to be the summation of the Froude-Kriloff force and the force by thewaves that are reflected by the hull (diffraction force).Ñ
  • 46. PART II DESIGN CONDITIONS-23-(b) Froude-Kriloff forceThe Froude-Kriloff force is the force derived by integrating the pressure of progressive waves around thecircumference of the hull. In the case of a moored vessel in front of a quaywall, it is taken to be the summationof the force of the incident waves and the force of the reflected waves from the quaywall.(c) Diffraction forceThe diffraction force acting on a vessel is the force that is generated by the change in the pressure field whenincident waves are scattered by the vessel’s hull. As an estimate, this change in the pressure field can bereplaced by the radiation force (the wave making resistance when the vessel moves at a certain velocitythrough a calm fluid) for the case that the hull is moved relative to fluid. It is assumed that the velocity of thevessel in this case is equal to the velocity of the cross section of the hull relative to the water particles in theincident waves. This velocity is referred to as the “equivalent relative velocity”.(d) Total force acting on the hull as a wholeThe total wave force acting on the hull as a whole can be obtained by integrating the Froude-Kriloff force andthe diffraction force acting on a cross section of the hull in the longitudinal direction from to.(2) Waves Forces by Diffraction Theory 13)In the case that the vessel in question is very fat (i.e., it has a block coefficient of 0.7 ~ 0.8), there are noreflecting structures such as quaywalls behind the vessel, and the motions of the vessel are considered to be verysmall, the vessel may be represented with an elliptical cylinder and the wave force may be calculated using anequation based on a diffraction theory 13).[3] Wind Load Acting on VesselThe wind load acting on a moored vessel shall be determined using an appropriate calculation formula.[Commentary]It is desirable to determine the wind load acting on a moored vessel while considering the temporal fluctuation of thewind velocity and the characteristics of the drag coefficients, which depend on the cross-sectional form of the vessel.[Technical Notes](1) The wind load acting on a vessel should be determined from equations (2.2.11) ~ (2.2.13), using the dragcoefficients and in the X and Y directions and the pressure moment coefficient about the midship.(2.2.11)(2.2.12)(2.2.13)where: drag coefficient in the X direction (from the front of the vessel): drag coefficient in the Y direction (from the side of the vessel): pressure moment coefficient about the midship: X component of the wind force (kN): Y component of the wind force (kN): moment of the wind load about the midship (kN•m): density of air; (t/m3)U: wind velocity (m/s): front projected area above the water surface (m2): side projected area above the water surface (m2): length between perpendiculars (m)(2) It is desirable to determine the wind force coefficients , , and through wind tunnel tests or water tanktests on a target vessel. Since such experiments require time and cost, it is acceptable to use the calculationequations for wind force coefficients 14),15) that are based on wind tunnel tests or water tank tests that have beencarried out in the past.(3) The maximum wind velocity (10-minute average wind velocity) should be used as the wind velocity U.(4) For the front projected area above the water surface and the side projected area above the water surface, it isdesirable to use the values for the target vessel. For standard vessel sizes, one may refer to regressionequations 1).(5) Since the wind velocity varies both in time and in space, the wind velocity should be treated as fluctuating in thex Lpp– 2¤=x Lpp 2¤=CbCX CY CMRX12---raU2ATCX=RY12---raU2ALCY=RM12---raU2ALLppCM=CXCYCMRXRYRMra ra 1.23 10 3–´=ATALLppCX CY CM
  • 47. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-24-analysis of the motions of a moored vessel. Davenport 16) and Hino have proposed the frequency spectra for thetime fluctuations of the wind velocity. The frequency spectra proposed by Davenport and Hino are given byequations (2.2.14) and (2.2.15), respectively./where: frequency spectrum of wind velocity (m2•s): average wind velocity at the standard height 10 m (m/s): friction coefficient for the surface defined with the wind velocity at the standard height; over theocean, it is considered that = 0.003 is appropriate.a: exponent when the vertical profile of the wind velocity is expressed by a power lawz: height above the surface of the ground or ocean (m)m: correction factor relating to the stability of the atmosphere; m is taken to be 2 in the case of a storm.[4] Current Forces Acting on VesselThe flow pressure force due to tidal currents acting on a vessel shall be determined using an appropriatecalculation formula.[Technical Notes](1) Current Pressure Force Due to Currents Coming onto the Bow of VesselThe current pressure force on the vessel due to currents coming onto the bow of a vessel may be calculated usingequation (2.2.16).(2.2.16)where: current pressure force (kN)S: wetted surface area (m2)V: flow velocity (m/s)(2) Current Pressure Force Due to Currents Coming onto the Side of VesselThe current pressure force due to a current coming onto the side of a vessel may be calculated using equation(2.2.17).(2.2.17)whereR: current pressure force (kN): density of seawater (t/m3) (standard value: = 1.03 t/m3)C: current pressure coefficientV: flow velocity (m/s)B: side projected area of hull below the waterline (m2)(3) The current pressure force due to tidal currents can in principle be divided into frictional resistance and pressureresistance. It is thought that the resistance to currents coming onto the bow of a vessel is predominantlyfrictional resistance, whereas the resistance to currents coming onto the side of a vessel is predominantlypressure resistance. However, in practice it is difficult to rigorously separate the two resistances and investigatethem individually. Equation (2.2.16) is a simplification of the following Froude equation with = 1.03,t = 15ºC and l = 0.14:(2.2.18)where: current pressure force (N): specific gravity of seawater (standard value: = 1.03)g: gravitational acceleration (m/s2)t: temperature (ºC)S: wetted surface area (m2)f Su f( ) 4KrU102 X21 X2+( )4 3¤----------------------------=(2.2.14)64748X 1200f= U10Su f( ) 2.856KrU102b--------------- 1fb---è øæ ö2+î þí ýì ü5– 6¤=(2.2.15)64748b 1.169 10 3–U10aKr-------------è øç ÷æ ö z10------è øæ ö2ma 1–´=Su f( )U10KrKrU z 10¤( )aµ[ ]Rf 0.0014SV2=RfR 0.5r0CV2B=r0 r0rwRf rwgl 1 0.0043 15 t–( )+{ }SV1.825=Rfrw rw
  • 48. PART II DESIGN CONDITIONS-25-V: flow velocity (m/s)l: coefficient (l = 0.14741 for a 30m-long vessel and l = 0.13783 for a 250m-long vessel)(4) The current pressure coefficient C in equation (2.2.17) varies according to the relative current direction q; thevalues obtained from Fig. T- 2.2.9 may be used for reference purposes.(5) Regarding the wetted surface area S and the side projected area below the waterline B, one may use valuesobtained from a regression equations 3) that have been derived by statistical analysis.Fig. T- 2.2.9 Current Pressure Coefficient C[5] Load-Deflection Characteristics of Mooring SystemWhen performing a motion analysis of a moored vessel, the load-deflection characteristics of the mooringsystem (mooring ropes, fenders, etc.) shall be modeled appropriately.[Technical Notes]The load-deflection characteristics of a mooring system (mooring ropes, fenders, etc.) is generally nonlinear.Moreover, with regard to the load-deflection characteristics of a fender, they may show hysteresis, and so it isdesirable to model these characteristics appropriately before carrying out the motion analysis of a moored vessel.2.2.4 Tractive Force Acting on Mooring Post and Bollard (Notification Article 79)(1) It shall be standard to take the values listed in Table 2.2.1 as the tractive forces of vessels acting onmooring posts and bollards.(2) In the case of a mooring post, it shall be standard to assume that the tractive force stipulated in (1) actshorizontally and a tractive force equal to one half of this acts upwards simultaneously.(3) In the case of a bollard, it shall be standard to assume that the tractive force stipulated in (1) acts in alldirections.Table 2.2.1 Tractive Forces of Vessels (Notification Article 79, Appended Table 12)Gross tonnage (GT) ofvessel (tons)Tractive force acting on amooring post (kN)Tractive force acting on abollard (kN)200 < GT ≦ 500 150 150500 < GT ≦ 1,000 250 2501,000 < GT ≦ 2,000 350 2502,000 < GT ≦ 3,000 350 3503,000 < GT ≦ 5,000 500 3505,000 < GT ≦ 10,000 700 50010,000 < GT ≦ 20,000 1,000 70020,000 < GT ≦ 50,000 1,500 1,000Currentpressurecoefficient+Relative current direction ( )G1.57.0Water depth Ddraft @ = 1.1
  • 49. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-26-[Commentary](1) “Mooring posts” are installed away from the waterline, either on or near to the mooring facilities, close to theboth ends of a berth so that they may be used for mooring a vessel in a storm. “Bollards”, on the other hand, areinstalled close to the waterline of the mooring facilities so that they may be used for mooring, berthing, orunberthing a vessel in normal conditions.(2) Regarding the layout and names of mooring ropes to moor a vessel, see Part ⅧⅧⅧⅧ, 2.1 Length and Water Depthof Berths.(3) Regarding the layout and structure of mooring posts and bollards, see Part ⅧⅧⅧⅧ , 19.3 Mooring Posts, Bollards,and Mooring Rings.[Technical Notes](1) It is desirable to calculate the tractive force acting on a mooring post and a bollard based on the breakingstrength of the mooring ropes possessed by a vessel arriving at the berth, the meteorological and oceanographicconditions at the place where the mooring facilities are installed, and the dimensions of vessels, and if necessaryalso considering the force due to a berthing vessel, the wind pressure on a moored vessel, and the force due tomotions of a vessel 9), 11). Alternatively, it is also possible to determine the tractive force acting on a mooringpost and a bollard in accordance with (2) ~ (6) below.(2) In the case that the gross tonnage of a vessel exceeds 5,000 tons and there is no risk of more than one mooringrope being attached to a bollard that is used for spring lines at the middle of mooring facilities for which thevessel’s berth is fixed, the tractive force acting on a bollard may be taken as one half of the value listed in Table2.2.1.(3) The tractive force due to a vessel whose gross tonnage is no more than 200 tons or greater than 100,000 tons(i.e., a vessel that is not covered in Table 2.2.1) should be calculated by considering the meteorological andoceanographic conditions, the structure of the mooring facilities, past measurement data on tractive force, etc.The tractive force on mooring facilities at which vessels are moored even in rough weather or mooring facilitiesthat are installed in waters with severe meteorological / oceanographic conditions should also be calculated byconsidering these conditions.(4) The tractive force acting on a mooring post has been determined based on the wind pressure acting on a vessel insuch a way that a lightly loaded vessel should be able to moor safely even when the wind velocity is 25 ~ 30m/s, with the assumption that the mooring posts are installed at the place away from the wharf waterline by theamount of vessel’s width and that the breast lines are pulled in a direction 45º to the vessel’s longitudinalaxis 17),18). The tractive force so obtained corresponds to the breaking strength of one to two mooring ropes,where the breaking strength of a mooring rope is evaluated according to the “Steel Ship Regulations” by theNippon Kaiji Kyokai. For a small vessel of gross tonnage up to 1,000 tons, the mooring posts can withstand thetractive force under the wind velocity of up to 35 m/s.The tractive force acting on a bollard has been determined based on the wind pressure acting on a vessel insuch a way that even a lightly loaded vessel should be able to moor using only bollards in a wind of velocity up to15 m/s, with the assumption that the ropes at the bow and stern are pulled in a direction at least 25º to the vessel’saxis. The tractive force so obtained corresponds to the breaking strength of one mooring rope for a vessel ofgross tonnage up to 5,000 tons and two mooring ropes for a vessel of gross tonnage over 5,000 tons, where thebreaking strength of a mooring rope is evaluated according to the “Steel Ship Regulations” by the Nippon KaijiKyokai.The tractive force for a bollard that is used for spring lines and is installed at the middle of a berth, for whichthe vessel’s berthing position is fixed, corresponds to the breaking strength of one mooring rope, where thebreaking strength of a mooring rope is evaluated according to the “Steel Ship Regulations” by the Nippon KaijiKyokai. Note however that, although there are stipulations concerning synthetic fiber ropes in the “Steel ShipRegulations” by the Nippon Kaiji Kyokai with regard to nylon ropes and type B vinylon ropes (both of whichare types of synthetic fiber rope), the required safety factor has been set large owing to the factors such that thereis little data on the past usage of such ropes and their abrasion resistance is low, and so both the required ropediameter and the breaking strength are large. Accordingly, in the case of berths for which the mooring vesselsuse only nylon ropes or type B vinylon ropes, it is not possible to apply the stipulations in (2) above.In the above-mentioned tractive force calculations, in addition to the wind pressure, it has been assumed thatthere are tidal currents of 2 kt in the longitudinal direction and 0.6 kt in the transverse direction.(5) When determining the tractive force from a small vessel of gross tonnage no more than 200 tons, it is desirableto consider the type of vessel, the berthing situation, the structure of the mooring facilities, etc. During actual50,000 < GT ≦ 100,000 2,000 1,000Gross tonnage (GT) ofvessel (tons)Tractive force acting on amooring post (kN)Tractive force acting on abollard (kN)
  • 50. PART II DESIGN CONDITIONS-27-design of mooring posts and bollards for vessels of gross tonnage no more than 200 tons, it is standard to takethe tractive force acting on a mooring posts to be 150 kN and the tractive force acting on a bollard to be 50 kN.(6) When calculating the tractive force in the case of vessels such as ferries, container ships, or passenger ships,caution should be exercised in using Table 2.2.1, because the wind pressure-receiving areas of such vessels arelarge.[References]1) Yasuhiro AKAKURA, Hironao TAKAHASHI, Takashi NAKAMOTO: “Statistical analysis of ship dimensions for the size ofdesign ship”, Tech. Note of PHRI, No. 910, 1998 (in Japanese).2) Yasuhiro AKAKURA and Hironao TAKAHASHI: “Ship dimensions of design ship under given confidence limits”, TechnicalNote of P.H.R.I., September 1998.3) PIANC: “Report of the International Commission for Improving the Design of Fender Systems”, Supplement to Bulletine No.45, 1984.4) Baker, A. L. L.: “The impact of ships when berthing”, Proc. Int’l Navig. Congr. (PIANC), Rome, Sect II, Quest. 2, 1953, pp.111-142.5) Masahito MIZOGUCHI, Tanekiyo NAKAYAMA: “Studies on the berthing velocity, energy of the ships”, Tech. Note ofPHRI, No. 170, 1973 (in Japanese).6) Hirokane OTANI, Shigeru UEDA, Tatsuru ICHIKAWA, Kensei SUGIHARA: “A study on the berthing impact of the bigtanker”, Tech. Note of PHRI, No. 176, 1974 (in Japanese).7) Shigeru UEDA: “Study on berthing impact force of very large crude oil carriers”, Rept. of PHRI, Vol. 20, No. 2, 1981, pp.169-209 (in Japanese).8) Myers, J.: “Handbook of Ocean and Underwater Engineering”, McGraw-Hill, New York, 1969.9) Shigeru UEDA, Eijiro OOI: “On the design of fending systems for mooring facilities in a port”, Tech. Note of PHRI, No. 596,1987 (in Japanese).10) Shigeru UEDA, Satoru SHIRAISHI: “On the design of fenders based on the ship oscillations moored to quaywalls”, Tech.Note of PHRI, No. 729, 1992 (in Japanese).11) Shigeru UEDA: “Analytical method of motions moored to quaywalls and the applications”, Tech. Note of PHRI, No. 504,1984 (in Japanese).12) Shigeru UEDA, Satoru SHIRAISI: “Method and its evaluation for computation of moored ship’s motions”, Rept. of PHRI,Vol. 22, No. 4, 1983 pp. 181-218 (in Japanese).13) Yoshimi GODA, Tomotsuka TAKAYAMA, Tadashi SASADA: “Theoretical and experimental investigation of wave forceson a fixed vessel approximated with an elliptic cylinder”, Rept of PHRI, Vol. 12, No. 4, 1994, pp. 23-74 (in Japanese).14) R. M. Isherwood: “Wind resistance of merchant ships”, Bulliten of the Royal Inst. Naval Architects, 1972, pp. 327-338.15) Shigeru UEDA, Satoru SHIRAISHI, Kouhei ASANO, Hiroyuki OSHIMA: “Proposal of equation of wind force coefficientand evaluation of the effect to motions of moored ships”, Tech. Note of PHRI, No. 760, 1993 (in Japanese).16) Davenport, A. G.: “Gust loading factors”, Proc. of ASCE, ST3, 1967, pp. 11-34.17) Hirofumi INAGAKI, Koichi YAMAGUCHI, Takeo KATAYAMA: “Standardization of mooring posts and bollards forwharf”, Tech. Note of PHRI, No. 102, 1970 (in Japanese).18) Iaso FUKUDA, Tadahiko YAGYU: “Tractive force on mooring posts and bollards”, Tech. Note of PHRI, No. 427, 1982 (inJapanese).
  • 51. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-28-Chapter 3 Wind and Wind Pressure3.1 GeneralWhen designing port and harbor facilities, meteorological factors such as winds, air pressure, fog, rainfall,snow depth, and air temperature should be considered.[Commentary]The effects that meteorological factors exert on the design of port and harbor facilities are as follows:(1) Air pressure and its distribution are the factors that govern the generations of winds and storm surge.(2) Wind is a factor that governs the generations of waves and storm surge, it exerts external forces on port andharbor facilities and moored vessels in the form of wind pressure, and it can disrupt port and harbor works suchas cargo handling.(3) Rainfall is a factor that determines the required capacity of drainage facilities in ports and harbors, and rain canalso disrupt port and harbor works such as cargo handling.(4) Fog is a factor that is an impediment to the navigation of vessels when they are entering or leaving a harbor, andalso decreases the productivity of port and harbor facilities.(5) In some cases, snow load is considered as a static load acting on port and harbor facilities.(6) Air temperature affects the stress distribution within structures of port and harbor facilities and may lead to theoccurrence of thermal stress in these structures.[Technical Notes](1) In calculations concerning the generation of storm surge or waves due to a typhoon, it is common to assume thatthe air pressure distribution follows either Fujita’s equation (3.1.1) or Myers’ equation (3.1.2); the constants inthe chosen equation are determined based on actual air pressure measurements in the region of typhoons.(Fujita’ formula) (3.1.1)(Myers’ formula) (3.1.2)wherep: air pressure at a distance r from the center of typhoon (hPa)r: distance from the center of typhoon (km): air pressure at the center of typhoon (hPa): estimated distance from the center of typhoon to the point where the wind velocity is maximum (km): air pressure drop at the center of typhoon (hPa);: air pressure at (hPa);The size of a typhoon varies with time, and so and must be determined as the functions of time.(2) With regard to wind, see 3.2 Wind.(3) Rain is generally divided into the rain of thunderstorms that have heavy rainfall in a short period of time and therain that continues for a prolonged period of time (rain by a typhoon is a representative example of the latter).When designing drainage facilities, it is necessary to determine the intensity of rainfall both for the case wherethe amount of runoff increases very rapidly and for the case where the runoff continues for a prolonged period.In the case of sewage planning whereby the intensity of rainfall during a thunderstorm is a problem, Sherman’sformula or Talbot’s formula is used.(Sherman’s formula) (3.1.3)(Talbot’s formula) (3.1.4)whereR: intensity of rainfall (mm/h)t: duration of rainfall (min)a, b, n: constants(4) With regard to snow load acting upon port and harbor facilities, see 15.3.4 Snow Load.p p¥Dp1 r r0¤( )2+--------------------------------–=p pc Dpr0r----–è øæ öexp+=pcr0Dp Dp p¥ pc–=p¥ r ¥= p¥ pc Dp+=r0 DpRatn----=Rat b+-----------=
  • 52. PART II DESIGN CONDITIONS-29-3.2 Wind (Notification Article 3, Clause 1)It shall be standard to set the wind characteristics for wave estimations and the wind characteristics as thecause of an external force on port and harbor facilities as stipulated in the following:(1) When calculating the wind velocity and wind direction used in estimations of waves and storm surges,either the actual wind measurements or the calculated values for gradient winds are to be used, withall necessary corrections having been made for the heights of measurements, etc.(2) The velocity of the wind acting on port and harbor facilities shall be set based on statistical data for anappropriate period in line with the characteristics of the facilities and structures.[Technical Notes](1) Gradient Winds(a) The velocity of the gradient wind can be expressed as a function of pressure gradient, radius of curvature ofisobars, latitude, and air density as in equation (3.2.1).(3.2.1)where: velocity of gradient wind (cm/s); in the case of an anticyclone, equation (3.2.1) gives a negative valueand so the absolute value should be taken.: pressure gradient (taken to be positive for a cyclone, negative for an anticyclone) (g/cm2/s2)r: radius of curvature of isobars (cm): angular velocity of Earths rotation ( );: latitude (º): density of air (g/cm3)Before performing the calculation, measurement units should first be converted into the CGS units listedabove. Note that 1º of latitude corresponds to a distance of approximately 1.11 × cm, and an air pressureof 1.0 hPa is g/cm/s2.(b) A gradient wind for which the isobars are straight lines (i.e., their radius of curvature in equation (3.2.1) isinfinite) is called the geostrophic wind. In this case, the wind velocity is .(2) The actual sea surface wind velocity is generally lower than the value obtained from the gradient wind equation.Moreover, although the direction of a gradient wind is parallel to the isobars in theory, the sea surface windblows at a certain angle a to the isobars as sketched in Fig. T- 3.2.2. In the northern hemisphere, the windaround a cyclone blows in a counterclockwise direction and inwards, whereas the wind around an anticycloneblows in a clockwise direction and outwards. It is known that the relationship between the velocity of gradientwinds and that of the actual sea surface wind varies with the latitude. The relationship under the averageconditions is summarized in Table T- 3.2.1. However, this is no more than a guideline; when estimating seasurface winds, it is necessary to make appropriate corrections by comparing estimations with actualmeasurements taken along the coast and values that have been reported by vessels out at sea (the latter arewritten on weather charts).Table T- 3.2.1 Relationship between Sea Surface WindSpeed and Gradient Wind SpeedFig. T- 3.2.2 Wind Direction for aCyclone (Low) and anAnticyclone (High)(3) When selecting the design wind velocity for the wind that acts directly on port and harbor facilities and mooredvessels, one should estimate the extreme distribution of the wind velocity based on actual measurement datataken over a long period (at least 30 years as a general rule) and then use the wind velocity corresponding to therequired return period.It is standard to take the wind parameters to be the direction and velocity, with the wind direction beingrepresented using the sixteen-points bearing system and the wind velocity by the mean wind velocity over 10minutes.Latitude 10º 20º 30º 40º 50ºAngle a 24º 20º 18º 17º 15ºVelocity ratio 0.51 0.60 0.64 0.67 0.70Vg rw f 1– 1¶p ¶r¤rarw2 2sin f-----------------------------++è øç ÷æ ösin=Vgp¶r¶-----w s 1– w 7.29 10 5– s¤´=fra107103V ¶p ¶r¤( ) 2rarw fsin( )¤=Low HighVs Vg¤
  • 53. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-30-In the Meteorological Agency’s Technical Observation Notes No. 34, the expected wind velocities with thereturn periods of 5, 10, 20, 50, 100 and 200 years for 141 government meteorological offices have beenestimated from the ten-minute mean wind velocity data of about 35 years, under the assumption that windvelocity follows a double exponential distribution. For locations with topographical conditions different fromthat of the nearest among the above-mentioned meteorological offices, one should conduct observations for atleast one year and then conduct a comparative investigation on topographical effects in order to make it possibleto use the aforementioned estimation results.(4) Regarding the wind velocity used in estimating storm surges and waves, it is standard to use the value at a heightof 10 m above sea level. The wind velocities obtained at government meteorological offices are the values for aheight of approximately 10 m above the ground level. Accordingly, when attempting to use such observedvalues to estimate sea surface winds, in the case that the elevations of the structural members are considerablydifferent from 10 m, it is necessary to correct the wind velocity with respect to the height. The vertical profile ofthe wind velocity is generally represented with a power law, and so in current design calculations for all kinds ofstructures, a power law is simply used: i.e.,(3.2.2)where: wind velocity at height h (m/s): wind velocity at height (m/s)The value of the exponent varies with the situation with regard to the roughness near to the surface of the groundand the stability of the atmosphere. In structural calculations on land, a value of n = 1/10 ~ 1/4 is used, and it iscommon to use a value of n ≧ 1/7 out to sea.Statistical data on wind velocity usually consider the ten-minute mean wind velocity. However, for somestructures the mean wind velocity over a shorter time period or the maximum instantaneous wind velocity maybe used, in which case it is necessary to gain an understanding of the relationship between the mean windvelocity over a certain time period and the maximum wind velocity, and also the characteristics of the gustfactor.3.3 Wind Pressure (Notification Article 3, Clause 2)The wind pressure shall be set appropriately, giving due consideration to the situation with regard to thestructural types of the facilities and their locations.[Technical Notes](1) When calculating the wind pressure acting on a moored vessel, one should refer to 2.2.3 [3] Wind Load Actingon a Vessel.(2) In the case that there are no statutory stipulations concerning the wind pressure acting on a structure, the windpressure may be calculated using equation (3.3.1).(3.3.1)wherep: wind pressure (N/m2)q: velocity pressure (N/m2)c: wind pressure coefficientEquation (3.3.1) expresses the wind pressure, i.e., the force due to the wind per unit area subjected to the windforce. The total force due to the wind acting on a member or structure is thus the wind pressure as given byequation (3.3.1) multiplied by the area of that member or structure affected by the wind in a plane perpendicularto the direction in which the wind acts.The velocity pressure q is defined as in equation (3.3.2).(3.3.2)whereq: velocity pressure (N/m2): density of air (kg/m3) = 1.23 kg/m3U: design wind velocity (m/s)The design wind velocity should be taken at 1.2 to 1.5 times the standard wind velocity (ten-minute mean windvelocity at a height of 10 m). This is because the maximum instantaneous wind velocity is about 1.2 to 1.5 timesthe ten-minute mean wind velocity.The wind pressure coefficient varies depending on the conditions such as the shape of the member orstructure, the wind direction, and the Reynolds number. With the exception of cases where it is determined bymeans of the wind tunnel experiments, it may be set by referring to the Article 87 of the “Enforcement OrderUh U0hh0-----è øæ ön=UhU0 h0p cq=q12---raU2=ra ra
  • 54. PART II DESIGN CONDITIONS-31-of the Building Standard Law” (Government Ordinance No. 338, 1950) or the “Crane Structure Standards”(Ministry of Labor Notification). With regard to wind direction, it is generally required to consider the winddirection that is most unfavorable to the structure, with the exception of cases where it has been verified thatthere exists an overwhelmingly prevailing direction of winds.
  • 55. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-32-Chapter 4 Waves4.1 General4.1.1 Procedure for Determining the Waves Used in Design (Notification Article 4, Clause 1)The waves used in the investigation of the stability of protective harbor facilities and other port and harborfacilities, as well as the examination of the degree of calmness of navigation channels and basins shall beset using wave data obtained from either actual wave measurements or wave hindcasting. Wavecharacteristics shall be obtained by carrying out necessary statistical processing and by analyzing wavetransformations owing to sea bottom topography and others. It shall be standard to carry out the wavehindcasting using a method that is based on an appropriate equation for representing the relationshipbetween the wind velocity and the wave spectrum or the significant wave parameters.[Commentary]The size and structural form of facilities are determinedby the factors such as the height and period of the wavesthat act on them. The setting of the wave conditions to beused in design should thus be carried out carefully. Thesetting of wave conditions should be carried outseparately for “ordinary waves” (i.e., waves that occur inordinary conditions: these are required when estimatingthe harbor calmness or the net working rate of cargohandling) and “storm waves” (i.e., waves that occur instorm conditions: these are required when estimating thewave force acting on structures).The waves that are obtained by statistically process-ing data based on either actual measurements or hindcast-ing are generally deepwater waves that are unaffected bythe sea bottom topography. Deepwater waves propagatetowards the coast, and once the waves reach to the waterdepth about one half the wavelength, they start to experi-ence the effects of topography and transform with theresult of wave height change. “Wave transformation”includes refraction, diffraction, reflection, shoaling, andbreaking. In order to determine the wave conditions at theplace where wave data is needed (for instance the placewhere a structure of interest is located), it is necessary togive appropriate consideration to such wave transforma-tions by means of numerical calculations or model exper-iments.In the above-mentioned procedure for setting thewave conditions to be used in design, it is necessary togive sufficient consideration to the irregularity of thewaves and to treat the waves as being of random natureas much as possible.[Technical Notes]A sample procedure for setting the wave conditions to be used in design is shown in Fig. T- 4.1.1.4.1.2 Waves to Be Used in DesignSignificant waves, highest waves, deepwater waves, equivalent deepwater waves and others shall be usedin the design of port and harbor facilities.[Commentary]The waves used in the design of structures are generally “significant waves”. The significant wave is a hypotheticalwave that is a statistical indicator of an irregular wave group. Significant waves have the dimensions that areapproximately equal to the values from visual wave observations, and so they are used in wave hindcasting. It is alsoknown that the period of a significant wave is approximately equal to the period at the peak of the wave spectrum.Because of such advantages, significant waves have been commonly used to represent wave groups. Nevertheless,depending on the purpose, it may be necessary to convert significant waves into other waves such as highest wavesand highest one-tenth waves.Wave data1)Actual measurement data2) Hindcasting valuesStatistical analysis1) Ordinary waves 2) Storm wavesWave occurrence rate ofdeepwater wavesWave transformationWave occurrence rateat the place of interestDesign deepwater wavesWave transformationParameters of design waves1) Significant wave2) Highest wave1)Wave force actingon structures2)Amount of wavesovertopping at seawalland revetments3) Others1) Harbor calmness2) Net working rate,number of working days3)Transport energy ofincoming waves4) OthersFig. T- 4.1.1 Procedure for Settingthe Waves to BeUsed in Design
  • 56. PART II DESIGN CONDITIONS-33-[Technical Notes](1) Definitions of Wave Parameters(a) Significant wave (significant wave height H1/3 and significant wave period T1/3)The waves in a wave group are rearranged in the order of their heights and the highest one-third are selected;the significant wave is then the hypothetical wave whose height and period are the mean height and period ofthe selected waves.(b) Highest wave (highest wave height Hmax and highest wave period Tmax)The highest wave in a wave group.(c) Highest one-tenth wave (H1/10, T1/10)The wave whose height and period are equal to the mean height and period of the highest one-tenth of thewaves in a wave group.(d) Mean wave (mean wave height , mean period )The wave whose height and period are equal to the mean height and period of all of the waves in a wavegroup.(e) Deepwater waves (deepwater wave height H0 and deepwater wave period T0)The waves at a place where the water depth is at least one half of the wavelength; the wave parameters areexpressed with those of the significant wave at this place.(f) Equivalent deepwater wave height (H0¢)A hypothetical wave height that has been corrected for the effects of planar topographic changes such asrefraction and diffraction; it is expressed with the significant wave height.(2) Maximum WaveThe largest significant wave within a series of significant wave data that was observed during a certain period(for example, one day, one month, or one year) is called the “maximum wave”. In order to clearly specify thelength of the observation period, it is advisable to refer to the maximum wave such as the “maximum significantwave over a period of one day (or one month, one year, etc.)”. Moreover, when one wishes to clearly state thatone is referring to the significant wave for the largest wave that occurred during a stormy weather, the term“peak wave” is used (see 4.4 Statistical Processing of Wave Observation and Hindcasted Data). The“maximum wave height” is the maximum value of the significant wave height during a certain period; this isdifferent from the definition of the “highest wave height”.(3) Significance of Equivalent Deepwater WavesThe wave height at a certain place in the field is determined as the result of transformations by shoaling andbreaking, which depend on the water depth at that place, and those by diffraction and refraction, which dependon the planar topographical conditions at that place. However, in hydraulic model experiments on thetransformation or overtopping of waves in a two-dimensional channel or in two-dimensional analysis by wavetransformation theory, planar topographical changes are not taken into consideration. When applying the resultsof a two-dimensional model experiment or a theoretical calculation to the field, it is thus necessary toincorporate in advance the special conditions of the place in question, namely the effects of planar topographicalchanges (specifically the effects of diffraction and refraction), into the deepwater waves for the place inquestion, thus adjusting the deepwater waves into a form whereby they correspond to the deepwater incidentwave height used for the experiment or theoretical calculation. The deepwater wave height obtained bycorrecting the effects of diffraction and refraction with their coefficients is called the “equivalent deepwaterwave height”.The equivalent deepwater wave height at the place for which design is being carried out is given as follows:(4.1.1)whereKr: refraction coefficient for the place in question (see 4.5.2 Wave Refraction)Kd: diffraction coefficient for the place in question (see 4.5.3 Wave Diffraction)4.1.3 Properties of Waves[1] Fundamental Properties of WavesFundamental properties of waves such as the wavelength and velocity may be estimated by means of thesmall amplitude wave theory. However, the height of breaking waves and the runup height shall beestimated while considering the finite amplitude effects.H TH0¢ KdKrH0=
  • 57. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-34-[Technical Notes](1) Small Amplitude Wave TheoryThe fundamental properties of waves are expressed as the functions of the wave height, period, and water depth.Various characteristics of shallow water waves as obtained as a first approximation by small amplitude wavetheory are listed below. Note that, with regard to the coordinates, the positive x direction is taken in the directionof wave travel and the positive z direction vertically upwards with z = 0 corresponding to the still water level.The water depth h is assumed to be constant and wave characteristics are assumed to be uniform in thetransverse direction (y direction).(a) Surface elevation (displacement from still water level) (m)(4.1.2)whereh: surface elevation (m)H: wave height (m)L: wavelength (m)T: period (s)(b) Wavelength (m)(4.1.3)whereh: water depth (m)g: gravitational acceleration (m/s2)(c) Wave velocity (m/s)(4.1.4)(d) Water particle velocity (m/s)whereu: component of water particle velocity in the x direction (m/s)w: component of water particle velocity in the z direction (m/s)(e) Water particle acceleration (m/s)where: component of water particle acceleration in the x direction (m/s2): component of water particle acceleration in the z direction (m/s2)h x t,( )H2----2pL------x2pT------t–è øæ ösin=LgT22p--------- 2phL----------tanh=CgT2p------ 2phL----------tanhgL2p------ 2phL----------tanh= =(4.1.5)644474448upHT-------=2p z h+( )L-----------------------cosh2phL----------sinh-----------------------------------2pL------x2pT------t–è øæ ösinwpHT-------=2p z h+( )L-----------------------cosh2phL----------sinh-----------------------------------2pL------x2pT------t–è øæ öcos(4.1.6)644474448dudt------2p2HT2-------------–=h2p z h+( )L-----------------------cos2phL----------sinh-----------------------------------2pL------x2pT------t–è øæ öcosdwdt-------2p2HT2-------------–=h2p z h+( )L-----------------------cos2phL----------sinh-----------------------------------2pL------x2pT------t–è øæ ösindudt------dwdt-------
  • 58. PART II DESIGN CONDITIONS-35-(f) Pressure in water when wave acts (N/m2)(4.1.7)wherer0: density of water (1.01~1.05 × 103 kg/m3 for seawater)(g) Mean energy of wave per unit area of water surface (J)(4.1.8)where Ek and Ep are the kinetic and potential energy densities respectively, with Ek = Ep.(h) Mean rate of energy transported in the direction of wave travel per unit time per unit width of wave (N • m/m/s)W = CG E = nCE (4.1.9)CG = nC (4.1.10)whereCG: group velocity of waves (m/s)(4.1.11)(2) Characteristics of Deepwater Waves and Wavelength(a) Deepwater wavesWaves in water with the depth greater than one-half the wavelength (h/L > 1/2) are called the deepwaterwaves. Various characteristics of deepwater waves may be obtained from the equations of small amplitudewave theory by letting h/L ® ∞ . The wavelength L0, wave velocity C0, and group velocity CG for deepwaterwaves thus become as below. Note that the units of period T are seconds (s).L0 = 1.56T 2(m), C0 = 1.56T (m/s)CG= 0.78T (m/s) (4.1.12)= 1.52T (kt)= 2.81T (km/h)As expressed in equation (4.1.12), the wavelength, wave velocity, and group velocity for deepwater wavesdepend only on the period and are independent of the water depth.(b) Wavelength of long wavesWaves for which the wavelength is extremely long compared with the water depth (h/L < 1/25) are called thelong waves. Various characteristics of long waves may be obtained from the equations of small amplitudewave theory by taking h/L to be extremely small. The wavelength, wave velocity, and group velocity for longwaves thus become as follows:(m) (4.1.13)(m/s)(3) Consideration of Finite Amplitude EffectsThe equations shown in (1) are not always accurate for general shallow water waves having a large height, andso it is sometimes necessary to use equations for finite amplitude waves. When carrying out calculations usingfinite amplitude wave equations, one should refer to “Handbook of Hydraulic Formulas” published by the JapanSociety of Civil Engineers. The amount of the errors in calculations that arise from the use of the smallamplitude wave theory varies according to the wave steepness H/L and the ratio of water depth to wavelength. Nevertheless, the error in wave parameters is usually no more than 20 ~ 30% with the exception of thehorizontal water particle velocity u.One of the finite amplitude effects of waves appears on the crest elevation hc relative to the wave height; theratio increases as the wave height increases. The definition of the crest elevation hc is shown at the top of Fig. T-4.1.2. This figure was drawn up based on wave profile records from the field. It shows the ratio of the highestcrest elevation obtained from each observation record to the highest wave height Hmax in that record as thefunction of relative wave height H1/3/h.p12---r0gH2p z h+( )L-----------------------cosh2phL----------cosh-----------------------------------2pL------x2pT------t–è øæ ösin r0gz–=E Ek Ep+18---r0gH2= =n12--- 14phL----------4phL----------sinh---------------------+è øç ÷ç ÷ç ÷æ ö=L T gh=C CG gh= =h L¤
  • 59. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-36-(4) Types of Finite Amplitude Wave TheoryThe finite amplitude wave theories include the Stokeswave theory, cnoidal wave theory, and others. In theformer, the wave steepness is assumed to be relativelylow, and the wave profile is represented as a series oftrigonometric functions. A number of researchers haveproposed several approximate series solutions. In thistheory, however, convergence of the series becomesextremely poor as the water depth to wavelength ratiodecreases. This means that the theory cannot be applied ifthe water depth to wavelength ratio is too small. On theother hand, the cnoidel wave theory is obtained by a per-turbation expansion method with the water depth towavelength ratio assumed to be extremely small, mean-ing that it is valid when the water depth to wavelengthratio is small. Errors become large, however, when thewater depth to wavelength ratio increases. In addition tothese two theories, there are also the hyperbolic wavetheory, in which a cnoidal wave is approximated as anexpansion of hyperbolic functions, and the solitary wavetheory, which is the asymptotic case of the cnoidal wavetheory when the wavelength approaches to infinity. Withthe exception of solitary wave theory, the equations in allof these finite amplitude wave theories are complicated,meaning that calculations are not easy. In particular, with the cnoidal wave theory, the equations contain ellipticintegrals, making them very inconvenient to handle. If Dean’s stream function method 1), 2) is adopted, then thewave profile and water particle velocity can be obtained with good accuracy right up to the point where the wavebreaks.(5) Application of Finite Amplitude Wave Theories to Structural DesignsNonlinear theories, which include finite amplitude wave theories, are applied to a wide variety of coastalengineering fields. However, there are still a large number of unknowns, and so, in the case of design at present,they are only applied to a limited number of fields such as those discussed below.(a) Maximum horizontal water particle velocity umax at each elevation below the wave crestThis information is vital in the estimation of the wave force on a vertical structural member. The equationsfrom the Stokes wave theory are used when the water depth to wavelength ratio is large, and the equationsfrom solitary wave theory are used when the water depth to wavelength ratio is small. An approximatecalculation may be carried out using the following empirical equation 3):(4.1.14)where the coefficient a is given as listed in Table T- 4.1.2.Table T- 4.1.2 Coefficient a for Calculation of Maximum Horizontal Water Particle Velocity(b) Wave shoalingWave shoaling, which occurs as the water depth decreases, may be calculated using a long wave theory thatincludes nonlinear terms. Alternatively, the cnoidal wave theory or hyperbolic wave theory may be applied tothis phenomenon (see 4.5.5 Wave Shoaling).(c) Rise and drop of the mean water levelThe mean water level gradually drops as waves approach the breaking point and then rises within the breakerzone toward the shoreline, as can be calculated from the theory of nonlinear interference between waves andcurrents. This mean water level change is taken into account for the calculation of the wave height change dueto random wave breaking (see 4.5.6 Wave Breaking).h/L a h/L a0.030.050.070.100.141.501.501.431.250.970.20.30.50.70.680.490.250.27Number ofdata pointsStandarddeviationMeanH1/3 / h(ηc)maxHmaxFig. T- 4.1.2 Relationship between MaximumCrest Elevation (hc)max/Hmax andRelative Wave Height H1/3/humax z( )pHT------- 1 aHh----è øæ ö1 2¤ z h+h-----------è øæ ö3+i hcos 2p z h+( )( ) L¤[ ]2ph( ) L¤[ ]sinh------------------------------------------------------=
  • 60. PART II DESIGN CONDITIONS-37-(d) Air gap of offshore structuresWhen determining the amount of air gap of offshore structures above the still water level, it is advisable toconsider the relative increase in the wave crest elevation due to the finite amplitude effect such as exhibited inFig. T-4.1.12.[2] Statistical Properties of WavesIn the design of port and harbor facilities, it shall be standard to consider the statistical properties of thewaves with regard to wave heights and periods and to use the Rayleigh distribution for the wave heights ofan irregular deepwater wave group.[Commentary]The assumption behind the theory of Rayleigh distribution is a precondition that the wave energy is concentrated inan extremely narrow band around a certain frequency. Problems thus remain with regard to its applicability to oceanwaves for which the frequency band is broad. Nevertheless, it has been pointed out that, so long as the waves aredefined by the zero-upcrossing method, the Rayleigh distribution can be applied to ocean waves as an acceptableapproximation.[Technical Notes](1) Expression of Rayleigh DistributionThe Rayleigh distribution is given by the following equation:(4.1.15)wherep(H/H): probability density function of wave heightsH : mean wave height (m)According to the Rayleigh distribution, the highest one-tenth wave height H1/10, the significant wave height, and the mean wave height H are related to one another by the following equations:(4.1.16)On average, these relationships agree well with the results of wave observations in situ.The highest wave height Hmax is difficult to determine precisely as will be discussed in (2) below, but ingeneral it may be fixed as in the following relationship:~ (4.1.17)The periods are related as follows:≒ ~ (4.1.18)It should be noted however that as waves approach the coast, waves with the heights greater than the breakinglimit begin to break and that their heights are reduced. Thus it is not possible to use the Rayleigh distribution forthe wave heights within the breaker zone.(2) Occurrence Probability of the Highest Wave HeightThe highest wave height Hmax is a statistical quantity that cannot be determined precisely; it is only possible togive its occurrence probability. If the wave height is assumed to follow a Rayleigh distribution, then theexpected value Hmax of Hmax , when a large number of samples each composed of N waves are ensembled, isgiven as follows:(4.1.20)It should be noted, however, that when Hmax is obtained for each of a large number of samples each containingN waves, there will be a considerable number of cases in which Hmax exceeds Hmax. Thus a simple use of Hmaxas the design wave might place structures on a risky side. One can thus envisage the method in which a waveheight (Hmax)m with m = 0.05 or 0.1 is used, where (Hmax)m is set such that the probability of the value of Hmaxexceeding (Hmax)m is m (i.e., the significance level is m). The value of (Hmax)m for a given significance level m isgiven by the following equation:(4.1.21)p H H¤( )p2---HH-----p4---HH-----è øæ ö2–î þí ýì üexp=H1 3¤H1 10¤ 1.27H1 3¤=H1 3¤ 1.60H=Hmax 1.6(= 2.0)H1 3¤Tmax T1 3¤ 1.1(= 1.3)THmax 0.706 lnN0.57722 lnN----------------+è øæ ö H1 3¤=Hmax( )m 0.706H1 3¤ lnNln 1 1 m–( )¤[ ]----------------------------------è øæ ö=678
  • 61. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-38-Table T- 4.1.4 lists the values obtained from this equation. Because Hmax is not a definite value but rather aprobabilistic variable, the value of Hmax / H1/3 varies greatly with N and m. However, considering the facts that thewave height only approximately follows a Rayleigh distribution and that the wave pressure formula has been derivedwhile containing a certain scatter of experimental data, it is appropriate to use Hmax = (1.6 ~ 2.0) H1/3 by neglectingthe very small or large values in the table.Table T- 4.1.4 Relationship between Highest Wave Height Hmax and Significant Wave Height H1/3[3] Wave SpectrumIn the design of port and harbor facilities, due consideration shall be given to the functional form of thewave spectrum and an appropriate expression shall be used.[Technical Notes](1) General Form of Wave SpectrumThe general form of the wave spectrum is usually represented as in the following equation:(4.1.22)wheref: frequencyq: azimuth from the principal direction of the waveS(f,q): directional spectrumIn the above, S(f) is a function that represents the distribution of the wave energy with respect to frequency; it iscalled the “frequency spectrum”. G(f,q) is a function that represents the distribution of the wave energy withrespect to direction; it is called the “directional spreading function”.The functions expressed in the following equations may be used for S(f) and G(f,q). The frequency spectrumof equation (4.1.23) is called the Bretschneider-Mitsuyasu spectrum, while equation (4.1.24) is called theMitsuyasu type spreading function.(4.1.23)(4.1.24)where G0 is a constant of proportionality that satisfies the following normalization condition:(4.1.25)where qmax and qmin are respectively the maximum and minimum angles of deviation from the principaldirection.The term S in equation (4.1.24) is a parameter that represents the degree of directional spreading of waveenergy. It is given by the following formulas::(4.1.26): ≦where fm is the frequency at which the spectrum peak appears. It may be represented in terms of the significantwave period T1/3 as in the following equation:(4.1.27)If the units of H1/3 and T1/3 are meters and seconds respectively, then the units of S(f,q) are m2•s.Number of wavesNMode(Hmax) mode50% significancelevel(Hmax) 0.5Mean(Hmax)10% significancelevel(Hmax) 0.15% significancelevel(Hmax) 0.05501002005001,0002,0005,00010,0001.40H1/31.52H1/31.63H1/31.76H1/31.86H1/31.95H1/32.05H1/32.12H1/31.46H1/31.58H1/31.68H1/31.81H1/31.91H1/32.00H1/32.10H1/32.19H1/31.50H1/31.61H1/31.72H1/31.84H1/31.94H1/32.02H1/32.12H1/32.19H1/31.76H1/31.85H1/31.94H1/32.06H1/32.14H1/32.22H1/32.31H1/32.39H1/31.86H1/31.95H1/32.03H1/32.14H1/32.22H1/32.30H1/33.39H1/32.47H1/3S f q,( ) S f( )G f q,( )=S f( ) 0.257H1 3¤ T21 3¤ f5–4–1.03 T1 3¤ f( )4––[ ]exp=G f q,( ) G0 i2Sq2---cos=G f q,( ) qdqminqmaxò 1=S Smaxffm-----è øæ ö2.5–= f fm>64748S Smaxffm-----è øæ ö5= f fmfm 1 1.05T1 3¤( )¤=
  • 62. PART II DESIGN CONDITIONS-39-(2) Value of Directional Spreading ParameterIt is standard to take a value of 10 for the maximum value Smax of the directional spreading parameter in the caseof wind waves in deep water. In the case of swell considering the process of wave decay and others, it isappropriate to take a value of 20 or more. Figure T- 4.1.4 shows a graph of approximately estimated values ofSmax against wave steepness. Judging by the value of wave steepness, it can be seen that Smax< 20 for windwaves. This graph may be used in order to set an approximate value for Smax. Goda and Suzuki 4)have proposedusing as the standard values Smax = 10 for wind waves, Smax = 25 for swell during initial decay, and Smax = 75 forswell that has a long decay distance.(3) Change in Smax Due to RefractionThe form of the directional spreading function changes as waves undergo the refraction process. When adiffraction calculation on irregular waves is carried out using waves that have been refracted, it is thus veryimportant to consider such changes in the directional spreading function. Figure T- 4.1.5 shows the values ofSmax after waves have been refracted at a coastline with straight and parallel depth contour lines. In the figure,(ap)0 is the incident angle of the principal wave direction at the deepwater boundary, i.e., the angle between theprincipal wave direction and the line normal to the depth contours.(4) Improved Model for Frequency SpectrumIf waves are generated in a laboratory flume using the Bretschneider-Mitsuyasu spectrum expressed by equation(4.1.23), the significant wave period of the generated waves often deviates from the target significant waveperiod. The reason for such a deviation is that the original equation (4.1.23) is given in terms of the peakfrequency fm, but this is replaced with the significant wave period T1/3 by using equation (4.1.27). Goda 54) hasthus proposed the following standard spectral form for which the significant wave period of the generated wavesdoes not deviate from the target significant wave period.(4.1.28)The peak frequency for equation (4.1.28) is about 8% lower than that for equation (4.1.23), the spectral densityat the peak is about 18% higher, and overall the spectrum is shifted towards the low frequency side. At the veryleast, it is advisable to use the spectral form expressed by equation (4.1.28) for the target spectrum in hydraulicmodel experiments.(5) Relationship between Wave Spectrum and Typical Values of Wave Characteristics(a) Wave spectrum and typical value of wave heightIf the probability density function for the occurrence of a wave height H is assumed to follow the Rayleighdistribution, then the relationship between the mean wave height H and the zeroth moment of the wave(αp)0h/L0SmaxFig. T- 4.1.4 Graph Showing Estimated Valuesof Smax against Wave SteepnessFig. T- 4.1.5 Graph Showing the Changein Smax Due to RefractionS f( ) 0.205H1 3¤ T21 3¤ f5–4–0.75 T1 3¤ f( )4––[ ]exp=
  • 63. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-40-spectrum m0 is given by equation (4.1.30), where the n-th moment of the wave spectrum is defined as inequation (4.1.29).(4.1.29)≒ (4.1.30)Using the relationship H1/3 = 1.60 , one arrives at the following relationship between the significant waveheight and the spectrum.≒ (4.1.31)According to the results of actual observations, it is often the case that the best relationship is. In the case of wave data from the shallow waters where the wave height is large, the wavesare highly nonlinear and so the relationship is satisfied. In either case, there is a very strongcorrelation between and m0. It is thus acceptable to use equation (4.1.31) and calculate the significantwave height from the spectrum.(b) Wave spectrum and typical value of periodWhen waves are defined using the zero-upcrossingmethod, the mean period Tz is given by the followingequation according to Rice’s theory.(4.1.32)Calculating the mean period using the Bretschneider-Mitsuyasu type spectrum gives the followingrelationship:(4.1.33)Figure T- 4.1.6 shows a comparison between the meanperiods T obtained from actually observed wave profilesand the mean periods Tz estimated from spectrumcalculations. The values of Tz / T are distributed in therange 0.6 ~ 1.0, with the mean being 0.83. In other words,the mean values obtained from wave profiles tend to beabout 20% greater than those calculated from themoments of spectra. The deviation from Rice’s theory isthought to have been caused by the presence of secondorder nonliner components in the high frequency range ofwave spectra.(6) Spectrum for Long-Period WavesThe above explanation concerns the spectra for wind waves and swell components that have a relatively shortperiod. For long-period wave components that have a period of tens of seconds or more, see 4.8 Long-periodWaves and Seiche.4.2 Method of Determining Wave Conditions to Be Used in Design4.2.1 Principles for Determining the Deepwater Waves Used in Design (Notification Article 4, Clause 2)The duration of statistical wave data used in setting the deepwater wave conditions for investigating thestability of the structures of port and harbor facilities etc. shall be determined appropriately, in dueconsideration to the functions of the port and harbor facilities and the characteristics of the structures.[Commentary](1) As for actual measurement data, a relatively long period of measurements (10 years or more) is desirable.However, when there is a lack of such actual measurement data, hindcasted values that have been obtained usingat least about 30 years’ worth of meteorological data should be used, with these being corrected by means of theavailable data of actual wave measurement.(2) When hindcasted values obtained from meteorological data are corrected using actual measurement data, it isnecessary that the measurement data should cover the period of 3 years at the minimum and contain aconsiderable number of cases of large storms. However, if waves were recorded during an extraordinary weatherthat only occurs once every a few tens of years and the values for these waves exceed all the hindcasted values,the observed values may be used to obtain the design deepwater waves.mn f nS f( ) fd0¥ò=H 2pm0= 2.5 m0HH1 3¤ 4.0 m0H1 3¤ 3.8 m0=H1 3¤ 4.0 m0=H1 3¤Mean ; 0.832Standard deviation ; 0.072N = 171 dataFig. T- 4.1.6 Frequency Distribution of theRatio of Mean Period Tz bySpectral Calculation to ActuallyMeasured Mean Period TTz m0 m2¤=Tz 0.74T1 3¤=
  • 64. PART II DESIGN CONDITIONS-41-(3) If there is absolutely no actual measurement data at the site of interest, or if the only measurement data availableis for extremely limited conditions, measurement data for a neighboring place with similar natural conditionsmay be used. In this case, NOWPHAS (Nationwide Ocean Wave Information Network for Ports and Harbors)data may be used.(4) If it is known that an extraordinary storm event occurred in the area before the period for which wavehindcasting using meteorological data is carried out (for example, in a previous decade), the record of such anevent should be taken into consideration.(5) When hindcasted values for a hypothetical typhoon are used, it is advisable to sufficiently investigate themagnitudes of past typhoons and the courses that they followed, and to even include an investigation on theoccurrence probability of such a typhoon.(6) When estimating deepwater waves using actual measurement data, it is neccessary to take into account the factthat the measured wave height has been affected by refraction and shoaling. Thus the wave height of thedeepwater waves should be corrected by dividing the measured height by the refraction coefficient and theshoaling coefficient. In this case, it is also necessary to consider changes in the wave direction.(7) If the significant wave height obtained from actual measurement data is more than one half of the water depth atthe measurement location, it is considered that this wave record has been affected by wave breaking. With suchwave data, the parameters of the deepwater waves should be estimated by means of wave hindcasting. Notehowever that, with regard to the hindcasted deepwater waves, significant waves for the measurement locationshould be estimated as described in 4.5 Transformations of Waves, and a comparison with the actualmeasurement data should be carried out.(8) It is advisable to determine the deepwater waves that will be used in design with consideration of the encounterprobability based on the return period and the lifetime of the structure in question. However, the way in whichthe encounter probability is interpreted will depend on the functions, importance and return on investment of thestructure, and other factors, and so it is not possible to determine it for the general case. It must therefore bedetermined independently for each individual case by the judgement of the engineer in charge. Here, the“encounter probability” means the probability that waves with a height larger than the return wave height for agiven return period occurs at least once during the lifetime of the structure in question.(9) When determing the deepwater waves that will be used in design, it is necessary to examine the external forceson and past damage of existing structures adjacent to the structure under design.(10) It is standard to set deepwater wave parameters separately for each direction of the sixteen-point bearings,although the directions for which the wave height is small and their effects on the structure are readily judged asnegligible may be excluded. The wave direction hereby refers to the direction of the irregular wave componentthat has the highest energy density, in other words, the principal direction. Since the wave force acting on thestructure in question will not change greatly when the wave direction changes by only a few degrees, it isacceptable in design to represent the wave direction using the sixteen-point bearing system.4.2.2 Procedure for Obtaining the Parameters of Design WavesFirst, deepwater waves shall be determined by following 4.2.1 Principles for Determining theDeepwater Waves Used in Design. Then, transformations due to refraction, diffraction, shoaling, andbreaking shall be evaluated. Finally, the waves that have the most unfavorable effects on the structure inquestion or facilities in the hinterland shall be used as the design waves.[Technical Notes]The parameters of the design waves are determined according to the following procedures:(1) The effects of wave transformation such as refraction, diffraction, shoaling, and breaking are applied to thedeepwater waves determined by following 4.2.1 Principles for Determining the Deepwater Waves Used inDesign, in order to determine the parameters of the design waves at the design location.(2) If the location in question is subject to special conditions (for example, disturbances from externally reflectedwaves or an increase in wave height due to concave corners), these should also be taken into account.(3) The wave force and other wave actions on the structure in question such as overtopping are determined for thewaves obtained above.(4) According to the various conditions related to wave actions, there can be cases where the wave force becomeslargest when the water level is low, and so investigations should be carried out for all conceivable water levels.(5) The above calculations are carried out for each possible direction in which the deepwater waves may come in.The deepwater waves for which the wave action is largest or for which the effects on the structure in question orfacilities in the hinterland are most unfavorable are chosen as the design waves.
  • 65. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-42-4.3 Wave Hindcasting4.3.1 GeneralWave hindcasting shall be carried out by using an appropriate hindcasting method.[Commentary](1) Wave hindcasting should be made in the following two steps:(a) Setting of the wind field(b) Calculation of wave development and attenuation.(2) The field where waves are generated and developed is called the fetch (or wind field), and it is characterized byfour parameters: wind velocity, wind direction, fetch length, and wind duration. Where the wind field is set, thewave development and attenuation should be calculated by using the most appropriate hindcasting method forthe wind field conditions.[Technical Notes]The wind field is to be set according to the following procedures:(a) Collection of surface weather charts and meteorological data.(b) Determination of the duration of hindcasting for each case.(c) Calculation of gradient winds from the surface weather charts.(d) Estimation of the sea surface winds by empirical formulas and data of measurement.(e) Preparation of the wind field chart.4.3.2 Wave Hindcasting in Generating AreaFor the hindcasting of waves in the generating area, the spectrum methods and the significant wavemethods are recommended as standard methods.[Commentary]The reliability of the results of the wave hindcast should be examined through the comparison with the wavemeasurement data.[Technical Notes](1) Spectral Methods(a) GeneralSpectral methods can be classified into the spectral component methods that have been developed byassuming that the components of the spectrum for each frequency and direction develop independently untilsome equilibrium state is reached 6),7), and the parameteric methods that are based on the idea that thedevelopment and decay of a wave spectrum can be described by a certain small number of parameters 8),9),10).With the former, the development of waves is described in terms of the influx of energy from the wind into thecomponent waves that make up the spectrum and the weak nonlinear interaction between component waves.With the latter, development of waves are treated as the overall result of strong nonlinear effects and a kind ofsimilarity mechanism is assumed with introduction of a few parameters. Calculations are carried out byformulating and solving the equations that govern the development and transformation processes of wavesusing the parameters.The accuracy of wave hindcasting by spectral methods has not been sufficiently investigated yet. However,since the accuracy of wave hindcasting depends greatly on the accuracy of estimating ocean winds, at presentit is reasonable to believe that the accuracy of spectral methods is comparable to that of significant wavemethods. Nevertheless, it should be noted that even for the same wave hindcasting model, results can vary by10 ~ 20% due to differences in the matters like the calculation mesh, the boundary conditions or empiricalconstants. Accordingly, it is necessary to investigate the validity and accuracy of hindcasted results bycomparing them with observation values (examples of such comparisons are given in references 6)~11)). Inparticular, an equilibrium spectral form is assigned as the limit of wave development in the current spectralmethods. It is thought that the accuracy of the supposed equilibrium spectrum itself affects the results greatly,and so it is a good idea to investigate the accuracy with regard to the functional forms of frequency spectrumor the directional spectrum. This is because the significant wave height is proportional to the square root of theintegral of the directional spectrum, meaning that the calculation is such that the significant wave height doesnot change very much even if the spectral form itself changes somewhat, and so it is considered that the mostrigorous way of carrying out evaluation is to examine the spectral form.The spectral methods have the following advantages over the significant wave methods.
  • 66. PART II DESIGN CONDITIONS-43-① The effects of the variations of wind speed and direction on wave development are physically welldescribed.② Appropriate estimation results on wave heights and periods are obtained even when the wind field movestogether with wave propagation.③ Wind waves and swell mixed sea conditions can be reproduced in one calculation.Accordingly, if the results of hindcasting using a significant wave method seem dubious, it is a good idea tomake hindcasting again using a spectral method. Incidentally, spectral methods have been researched anddeveloped while primarily focusing on deepwater waves. There are only a few studies concerning shallowwater waves, namely Collins 12), Cavaleri 13), Golding 14) and Yamaguchi et al.(b) Details 6),7)Wave forecasting methods by mean of wave spectrum have been developed by many researchers since the1960s. Those developed by Japanese reserchers include Inoue’s model 6), Isozaki and Uji’s MRI model 7), andYamaguchi and Tsuchiya’s model. The basis of these models is the following energy balance equation:(4.3.1)where: energy density of a two-dimensional wave spectrum: linear amplifying factor in Phillips’ resonance theory 15): exponential amplifying factor in Miles’ theory 16): energy dissipated due to wave breaking: energy loss due to internal friction during wave propagations etc.: energy exchange due to the nonlinear interaction between component waves: component wave frequency and anglet: timex: position vector: group velocity vectorU: wind velocity: differential operator(2) Significant Wave Methods(a) S-M-B method① General 19),20)The S-M-B method is used when the wind field is stationary. The height and period of deepwatersignificant waves are estimated from the wind velocity and wind duration in the fetch and the fetch lengthusing Fig. T- 4.3.1. Of the wave height obtained from the wind velocity and that from the wind duration,the lower one is adopted as the hindcasted value; likewise for the period. Figure T- 4.3.1 has been drawnbased on the relationships by equations (4.3.2), (4.3.3) and (4.3.4), which were rewritten by Wilson 21) in1965.(4.3.2)(4.3.3)(4.3.4)where: significant wave height (m): significant wave period (s)U: wind velocity at 10 m above sea surface (m/s).F: fetch length (m)g: acceleration of gravity (m/s2) (= 9.81 m/s2)t: minimum duration (hr)¶¶t----E f q t x, , ,( ) CG f( )–= ÑE f q t x, , ,( ) a f U,( ) b f U,( )E F q t x, , ,( ) F3 F4 F5+ + + + +E F q t x, , ,( )a f U,( )b f U,( )F3F4F5f q,CG f( )ÑgH1 3¤U2--------------- 0.30 111 0.004gFU2------è øæ ö1 2¤+î þí ýì ü2----------------------------------------------------–=gT1 3¤2pU-------------- 1.37 111 0.008gFU2------è øæ ö1 3¤+î þí ýì ü5----------------------------------------------------–=t iFdCG-------0Fò iFdgT1 3¤ 4p¤------------------------0Fò= =H1 3¤T1 3¤
  • 67. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-44-Fig. T - 4.3.1 Wave Forecasting Diagram by the S-M-B Method② Handling of the effective fetch lengthWhen the fetch width is small relative to the fetch length (for example, in a long bay), the fetch length isdetermined by the distance to the opposite shore. If the distance to the opposite shore varies greatly whenthe direction is changed only slightly, it is advisable to use the effective fetch length defined by in equation(4.3.5) 22) when hindcasting is made.(4.3.5)where:effective fetch length (km):distance to opposite shore in the i-th direction (km):angle between the direction of Fi and the predominant wind direction (º)(b) Wilson’s method 21), 23)Wilson’s method is an extension of the S-M-B method. It includes improvements that it can be applied even toa moving fetch, for example in the case of a typhoon. Using the H1/3-t-F-T1/3 graph shown in Fig. T- 4.3.2, thepropagation of waves is traced in the F-T plane, while the development of the significant wave height andperiod are traced in the H1/3-t plane and T1/3-t plane, respectively. This figure has been obtained by calculationbased on equations (4.3.2), (4.3.3) and (4.3.4).(c) Hindcasting for shallow water wavesMethods that consider the influence of the water depth on wave development (i.e., the energy loss due tofriction with the sea bottom) include the Sakamoto-Ijima method. It is known from experience that thesignificant wave period and the significant wave height satisfy the following relationship. (Note however thatthis applies only for wind waves within the fetch area.)(4.3.6)where:significant wave height (m):significant wave period (s)WindSpeedH13 (m) T13 (s) t (h) T13H 13( )2= const.FetchFeffSFi2qicosS qicos------------------------=FeffFiqiT1 3¤ 3.86 H1 3¤=H1 3¤T1 3¤
  • 68. PART II DESIGN CONDITIONS-45-Fig. T- 4.3.2 H1/3-t-F-T1/3 Graph (from Wilsons equations (1965))In the Sakamoto-Ijima method, the ideas in Wilson’s method for deep water waves have been incorporatedinto the case for shallow water waves, resulting in an H1/3-t-F-CG graph such as shown in Fig. T- 4.3.3. Withuse of such a graph it possible to carry out the hindcasting of shallow water waves in a variable fetch.Fig. T- 4.3.3 H1/3-F-CG Graph for Shallow Water Waves (Sakamoto-Ijima Method)(A) Note: The numbers on the graphshow wind velocity (m/s),with water depth (m) in brackets
  • 69. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-46-4.3.3 Swell HindcastingWhen swell hindcasting is necessary, it is standard to use the Bretschneider method.[Commentary]Swell hindcasting methods include the Bretschneider method 24), the P-N-J method 5), and spectral methods. With theBretschneider method, the wave height and period of swell are hindcasted from the parameters of the significantwave. With the P-N-J method, the swell parameters are obtained by estimating the effects of the velocity dispersionand directional spreading of spectral components. With spectral methods as mentioned above, numerical calculationsare used; generally, no distinction is made between waves and swell in the generating area, with calculations for thecomponent waves at all of the different frequencies being carried out simultaneously, and the results being thesignificant wave parameters for the combination of wind waves and swell. If a significant wave method is used in thehindcasting of waves in the generating area, it is necessary to hindcast swell, in which case it is standard to use theBretschneider method, which is relatively simple and easy to use. Note however that the amount of reliableobservation data that has been obtained for swell is insufficient, and so the hindcasting accuracy is lower than that forwaves in the generating area. Accordingly, it is necessary to treat swell hindcast values as representing no more thanapproximate values, and it is advisable to use them only after carrying out a comparative investigation with actualmeasurement data.[Technical Notes]In the Bretschneider method, swell hindcasting is carried out by using Fig. T- 4.3.4.Fig. T- 4.3.4 Swell Hindcasting DiagramThe term Fmin in the diagram is the minimum fetch length, D is the decay distance of the swell, HF and TF are theheight and period of the significant wave at the end of the fetch respectively, and HD and TD are the height and periodof the significant wave at the swell hindcasting point respectively. If the significant wave height and period aredetermined by the wind velocity and the fetch length in the S-M-B method, the minimum fetch length Fmin is equal tothe actual fetch length. If the wave development is governed by the wind duration, then Fmin is the fetch lengthcorresponding to that wind duration and wind velocity.The time t required for waves to propagate over the decay distance D is calculated from the following equation:(4.3.7)where:group velocity corresponding to (m/s)tDCGD-----------4pDgTD-----------= =CGD TD
  • 70. PART II DESIGN CONDITIONS-47-4.4 Statistical Processing of Wave Observation and Hindcasted Data(1) Wave characteristics shall be expressed as joint distributions of wave height and period by wavedirection using the monthly, seasonal, and annual wave data.(2) Storm wave data shall be sorted by the peaks-over-threshold method so as to yield the data set ofextreme wave heights for extreme statistical analysis, and the extreme wave heights shall beexpressed in terms of the return perid.[Commentary](1) The wave distribution characteristics for ordinary conditions are expressed separately for each wave direction asa joint distribution of wave height and period. Observation data are often available for the wave height and theperiod, and so it is standard to use such data. If observation data are not available, then hindcast data is used.Since waves in ordinary conditions are often affected by the local wind, it is necessary to gain a sufficientunderstanding of the local wind characteristics. There is generally not much observation data available for thewave direction, and so it is standard to use hindcasting. It is necessary to give sufficient consideration to theeffects of swell.(2) It is standard to represent the height of waves used in the design of protective facilities as the “return waveheight” for the return period of the “peak waves” using data over a long time period (at least 30 years as ageneral rule). Since there are only a few places at which observation data extending over such a prolonged timeduration are available, generally hindcast data must be used.(3) The peak waves, basic data for estimating the return wave height, are the wave (generally the significant wave)at the time for which the wave height becomes largest during the process of wave development and decay undera certain meteorological condition. It is thought that sampled peak waves are mutually independent in statisticalsense. When estimating the return wave height, it is possible to use the time series of data for which the peakwaves exceed a certain threshold value during the period in question. Alternatively, it is possible to obtain themaximum value of the “peak waves” for each year, and then use the data as the annual maximum wave. In eithercase, the theoretical distribution function of the return wave height is not known, and so one should try to fitseveral distribution functions such as the those of the Gumbel distribution and the Weibull distribution, find thefunctional form that best fits the data, and then extrapolate it in order to estimate the return wave heights for anumber of different return periods (say 50 years, 100 years, etc.). The accuracy of the resulting estimated valuesdepends largely on the reliability of the data used rather than on the statistical processing method. When drawingup the data set of peak waves using wave hindcasting, it is thus necessary to take due care in appropriatelyselecting the hindcasting method and to closely inspect the hindcasted results.(4) With regard to the wave period corresponding to the return wave height, the relationship between the waveheight and the wave period is plotted for the data of peak waves (which have been used in estimating the returnwave height), and then the wave period is determined appropriately based on the correlation between the two.[Technical Notes](1) Estimation of Return Wave HeightDuring statistical processing, the wave heights arerearranged in the descending order, and the probability ofeach value of wave height not being exceeded iscalculated. If there are N data and the m-th largest waveheight is denoted with xm,N, then the probability P that thewave height does not exceed xm,N is calculated using thefollowing equation:≦ (4.4.1)The values used for a and b in this equation depend on thedistribution function. Specifically, values such as those inTable T- 4.4.1 are used. The values used for the Gumbeldistribution were determined by Gringorten 25) in such a way as to minimize the effects of statistical scatter inthe data. The values used for the Weibull distribution were determined by Petruaskas and Aagaard 26) using thesame principle.It is commented that the Thomas plot often used in hydrology corresponds to the case a = 0, b = 1, and theHazen plot corresponds to the case a = 0.5, b = 0.The distribution functions used in hydrology include the Gumbel distribution (double exponentialdistribution), the logarithmic extreme value distribution, and the normal distribution (in the last case, the datamust first be transformed appropriately). Since the data on peak wave heights have not been accumulated over aprolonged period of time, it is not well known which distribution function is most suitable.Table T- 4.4.1 Parameters Used in Calculating theProbability not Exceeding a Certain Wave HeightDistribution function a bGumbel distributionWeibull distribution (k = 0.75)“ (k = 0.85)“ (k = 1.0)“ (k = 1.1)“ (k = 1.25)“ (k = 1.5)“ (k = 2.0)0.440.540.510.480.460.440.420.390.120.640.590.530.500.470.420.37P H[ xm N, ] 1m a–N b+--------------–=
  • 71. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-48-Following Petruaskas and Aagaard, we thus introduce the method whereby one tries fitting eight distributionfunctions, namely the Gumbel distribution function (equation (4.4.2)) and the Weibull distribution function(equation (4.4.3)) with k = 0.75, 0.85, 1.0, 1.1, 1.25, 1.5 and 2.0; the distribution function that best fits the dataon any particular data set is then selected as the extreme distribution for that data set.≦ (Gumbel distribution) (4.4.2)≦ (Weibull distribution) (4.4.3)In order to fit the data to the distribution function, the “non-exceedance probability” (probability not exceeding acertain wave height) P is transformed into the variable using equation (4.4.4) or (4.4.5).≦ (Gumbel distribution) (4.4.4)≦ (Weibull distribution) (4.4.5)If the data fit equation (4.4.2) or (4.4.3) perfectly, then there will be a linear relationship between x and .Accordingly, the data are assumed to follow the linear relationship shown in equation (4.4.6). The parameters Aand B are determined using the method of least squares, thus giving an equation for estimating the return waveheight.(4.4.6)where and are the estimated values of the parameters A and B in equation (4.4.2) or (4.4.3), respectively.The return period Rp of the wave height H is related to the non-exceedance probability P (H ≦ x) as in thefollowing:or (4.4.7)≦whereK: number of years during the period for which analysis was carried outN: number of data of peak waves(2) Candidate Distribution Functions and Rejection EriteriaGoda has proposed the following method 51) ~ 53), which is a revised version of the method introduced above.(a) Addition of the Fisher-Tippett type II distribution to the candidate distributionsThe Fisher-Tippett type II distribution is given by the following equation.≦ (4.4.8)The following nine functions are employed as the candidate functions to be tried for fitting: the Gumbeldistribution function (equation (4.4.2)), the Weibull distribution function (equation (4.4.3)) with k = 0.75, 1.0,1.4 and 2.0 (four preset values), and the Fisher-Tippett type II distribution function with k = 2.5, 3.33, 5.0 and10.0 (four preset values).In place of the values listed in Table T- 4.4.1, the following equations are used for a and b in equation(4.4.1):For the Gumbel distribution,a = 0.44, b = 0.12 (4.4.9)For the Weibull distribution,(4.4.10)For the Fisher-Tippett type II distribution,(4.4.11)P H[ x]x B–A------------è øæ ö–î þí ýì üexp–exp=P H[ x] 1x B–A------------è øæ ök–î þí ýì üexp–=rv x B–( ) A¤=( )rv ln lnP H[–{–= x]}rv ln 1 P H[–{–[= x]}]1 k¤rvx A= ^ rv Bˆ+ ^A^ Bˆ^RpKN----11 P H x£( )–-------------------------------·=≦P H( x) 1KNRp----------–=P H[ x] 1 x B–( ) kA( )¤+{ }k––[ ]exp=a 0.20 0.27 k+=b 0.20 0.23 k+=a 0.44 0.52 k¤+=b 0.12 0.11 k¤–=
  • 72. PART II DESIGN CONDITIONS-49-(b) Selection of the best function through introduction of rejection criteriaInappropriate functions are rejected by means of two sets of criterion. The first is the REC criterion. For theresidual of the correlation coefficient for each distribution function, the 95% non-exceedance probability levelis determined in advance. If the residual of the correlation coefficient exceeds this threshold value for adistribution function when the extreme value data is fitted to that distribution function, the function in questionis rejected as being inappropriate. The second is the DOL criterion. The maximum value in the data is madedimensionless using the mean and standard deviation for the whole data. If this value is below the 5% orabove the 95% level of the cumulative distriburion of dimensionless deviation of the distribution functionbeing fitted, that function is rejected as being inappropriate. Next, the best function is selected not simplyaccording to the value of the correlation coefficient, but rather according to the MIR criterion, This criteriontakes into account the fact that the mean of the residual of the correlation coefficient relative to 1.0 will varyaccording to the distribution function. The function for which the ratio of the residual of the correlationcoefficient of the sample to the mean residual for the fitted distribution is lowest is judged to be the best fittingdistribution function.4.5 Transformations of Waves4.5.1 General (Notification Article 4, Clause 3)As a general rule, the waves to be considered to exert actions on port and harbor facilities shall be thewaves that are most unfavorable in terms of the structure stability or the usage of the port and harborfacilities. In this consideration, appropriate attention shall be given to wave transformations during thepropagation of waves from deepwater toward the shore, which include refraction, diffraction, shoaling,breaking, and others.4.5.2 Wave RefractionThe phenomenon of wave refraction occurs in intermediate depth to shallow waters. This is due to thechange in local wave velocity caused by the change in water depth. The changes in wave height and wavedirection due to refraction shall be considered.[Technical Notes](1) Refraction Calculations for Regular Waves(a) Refraction phenomenon and refraction coefficient (see Fig. T- 4.5.1)If waves are obliquely incident on a straight boundary where the water depth changes from h1 to h2, waves arerefracted at the boundary due to the change in wave velocity caused by the change in water depth. Supposethat the distance between wave rays changes from b1 to b2 as a result. If the change in the wave ray width isnot so large, it can be assumed that no wave energy flux cuts across the wave ray and flows out. If othersources of energy loss such as the friction along the sea bottom are ignored, then the continuity in the flux ofenergy transport results in the change of the wave height H1 at water depth h1 to the wave height H2 at waterdepth h2 as given by the following equation:(4.5.1)whereCG1 , CG2: group velocities at water depths h1 and h2, respectively (m/s)b1 , b2: distances between wave rays at water depths h1 and h2, respectively (m)In the equation, represents the change in wave heightdue to refraction, while represents the change inwave height due to the change in water depth. Using the shoalingcoefficient (see 4.5.5 Wave Shoaling), can berepresented as = , where Ks1 and Ks2 arethe shoaling coefficients at water depths h1 and h2, respectively.Suppose that the wave ray width, which is b0 for deepwaterwaves, changes to b due to the refraction phenomenon. The ratioof the wave height after the change to the original wave height inthis case is called the “refraction coefficient”. The refractioncoefficient Kr is given by the following equation:(4.5.2)H2H1------CG1CG2----------b1b2-----=water depth h1water depth h2Fig. T- 4.5.1 Schematic Diagramof Wave Refractionb1 b2¤CG1 CG2¤CG1 CG2¤CG1 CG2¤ Ks2 Ks1¤Kr b0 b¤=
  • 73. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-50-(b) Refraction calculation methodsRefraction calculation methods for regular waves include the wave ray methods in which calculations using acomputer are made possible, and the numerical wave propagation analysis methods 27) in which surface waveequations are solved by computers using finite difference schemes. An appropriate calculation method ischosen in accordance with the situation.Note however that for a coastline for which the depth contours are straight and parallel to one another, thechange in the wave direction and the refraction coefficient can be calculated using the following equations:(4.5.3)(4.5.4)Here, L, a and a0 denote the wavelength at water depth h, the angle of incidence of the wave at water depth h,and the angle of incidence of the wave in deep water, respectively. Figures T- 4.5.2 and T- 4.5.3 show therefraction coefficient and the wave direction, as calculated using equations (4.5.4) and (4.5.3), respectively.(2) Range of Application of Refraction Calculations Using Regular WavesBased on the principles behind calculations for regular waves, such calculations are applicable for waves forwhich there is little directional spreading and the frequency band is narrow; for example, swell-type waves andtsunamis. For waves like wind waves for which there is much directional spreading and the frequency band isbroad, it is necessary to carry out refraction calculations for irregular waves. Nevertheless, comparing the graphsshowing changes in the refraction coefficient and wave direction for regular waves and irregular waves at a coastasin a0sin2phL----------tanh=Kra0cosacos---------------=Fig. T- 4.5.2 Refraction Coefficient of Regular Waves at Coastwith Straight, Parallel Depth ContoursFig. T- 4.5.3 Graph Showing the Change in the Wave Direction of Regular Wavesat Coast with Straight, Parallel Depth Contours
  • 74. PART II DESIGN CONDITIONS-51-with straight, parallel depth contours, it can be seen that there is only a little difference between regular wavesand irregular waves in this case. This means that when the topography of a coastline is monotonous to the extentthat the depth contours are considered to be straight and parallel to the shoreline, the difference between theresults of refraction calculations for regular waves and irregular waves is usually only slight, and so the resultsof refraction calculations using regular waves can be used as a good approximation.(3) Refraction Calculations for Irregular Waves(a) Calculation methodsRefraction calculation methods for irregular waves include the following: ① the component wave method,whereby the directional wave spectrum is divided into an appropriate number of component waves, arefraction calculation is performed for each component wave, and then the refraction coefficient for theirregular wave is evaluated by making a weighted average of the component wave energies; ② methods inwhich the wave energy balance equation 28) or the mild-slope wave equation is solved directly using acomputer with finite difference schemes. As with the component wave method, the energy balance equation isderived by assuming that wave energy does not cut across wave rays and flow out. This means that thetechnique is basically the same in both cases. However, with the energy balance equation method, refractionwithin a small but finite region is calculated, meaning that the refraction coefficient does not become infiniteeven at a point in which two regular wave rays may converge. On the other hand, the mild-slope waveequation method is a strictly analytical method, but it is difficult to apply it to a large region. Whendetermining the refraction coefficient for irregular waves, it is acceptable to use the component wave method,which involves the linear superposition of refraction coefficients for regular waves and is thus simple andconvenient. However, when intersections of wave rays occur during a refraction calculation for a componentwave, the energy balance equation method may be used for practical purposes with the exception of the casethat the degree of intersection is large.(b) Effects of diffractionWhen deepwater waves have been diffracted by an island or a headland, the wave spectrum becomes generallydifferent from a standard form that has been assumed initially. Thus it is necessary to use the spectral formafter diffraction when performing the refraction calculation.(c) Diagrams of the refraction coefficient and angle for irregular waves at a coast with straight, parallel depthcontoursFigures T- 4.5.4 and T- 4.5.5 show the refraction coefficient Kr and the principal wave direction ap,respectively, for irregular waves at a coast with straight, parallel depth contours, with the principal direction ofdeepwater waves (ap)0 as the parameter. The direction (ap)0 is expressed as the angle between the wavedirection and the line normal to the boundary of deepwater. Smax is the maximum value of the parameter thatexpresses the degree of directional spreading of wave energy (see 4.1.3 [3] Wave Spectrum).Fig. T- 4.5.4 Refraction Coefficient of Irregular Waves at Coastwith Straight, Parallel Depth Contours
  • 75. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-52-Fig. T- 4.5.5 Change Due to Refraction in the Principal Direction ap of Irregular Wavesat Coast with Straight, Parallel Depth Contours(4) At places where the water depth is no more than about one half of the deepwater wave height, waves exhibit thecharacteristics of flow rather than those of undulations. This means that refraction calculations for wavedirections and refraction coefficients can only be applied to the water where the depth is at least one half of thedeepwater wave height.4.5.3 Wave Diffraction[1] DiffractionThe wave height in regions in which waves are anticipated to be greatly affected by the phenomenon ofdiffraction caused by obstacles such as breakwaters or islands shall be calculated using an appropriatemethod.[Commentary]Diffraction is a phenomenon whereby waves wheel into a region that is screened by something like a breakwater. It isthe most important phenomenon when determining the wave height in a harbor. The irregularity of waves should beconsidered in a diffraction calculation. For a harbor within which the water depth is assumed uniform, the diffractiondiagrams for irregular waves with regard to a semi-infinite breakwater or a straight breakwater that has just oneopening have been prepared. The ratio of the wave height after diffraction to the incident wave height is called thediffraction coefficient Kd. In other words, the diffraction coefficient Kd is given by the following equation:(4.5.10)whereHi: incident wave height outside harborHd: height of wave in harbor after diffractionDiffraction diagrams and diffraction calculation methods assume that the water depth within the harbor is uniform. Ifthere are large variations in water depth within the harbor, the errors will become large, in which case it is advisableto investigate the wave height in the harbor by means of either hydraulic scale model tests or else numericalcalculation methods that also take refraction into account.[Technical Notes](1) Diffraction Diagrams for Irregular WavesFigures T- 4.5.6 (a) ~ (c) show the diffraction diagrams by a semi-infinite breakwater for irregular waves withthe directional spreading parameter Smax = 10, 25, and 75. Figures T- 4.5.6 (a) ~ (llll) show the diffractiondiagrams through an opening of B/L = 1, 2, 4, and 8 for irregular waves with Smax = 10, 25, and 75.Kd Hd Hi¤=
  • 76. PART II DESIGN CONDITIONS-53----- Period ratio ─ Diffraction coefficientFig. T - 4.5.6(a) Diffraction Diagram by Semi-infinite Breakwaters (θ= 90º) for Smax = 10Wave directionWave direction
  • 77. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-54----- Period ratio ─ Diffraction coefficientFig. T - 4.5.6(b) Diffraction Diagram by Semi-infinite Breakwaters (θ= 90º) for Smax = 25Wave directionWave direction
  • 78. PART II DESIGN CONDITIONS-55----- Period ratio ─ Diffraction coefficientFig. T - 4.5.6(c) Diffraction Diagram by Semi-infinite Breakwaters (θ= 90º) for Smax = 75Wave directionWave direction
  • 79. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-56-Period ratio Diffraction coefficientPeriod ratio Diffraction coefficientFig. T - 4.5.7(a) Diffraction Diagram by Breakwaters with an Opening (B/L= 1.0) for Smax = 10Wave directionWavedirection
  • 80. PART II DESIGN CONDITIONS-57-Period ratio Diffraction coefficientPeriod ratio Diffraction coefficientFig. T - 4.5.7(b) Diffraction Diagram by Breakwaters with an Opening (B/L= 1.0) for Smax = 25Wave directionWave direction
  • 81. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-58-Period ratio Diffraction coefficientPeriod ratio Diffraction coefficientFig. T - 4.5.7(c) Diffraction Diagram by Breakwaters with an Opening (B/L= 1.0) for Smax = 75Wave directionWave direction
  • 82. PART II DESIGN CONDITIONS-59-Period ratio Diffraction coefficientPeriod ratio Diffraction coefficientFig. T - 4.5.7(d) Diffraction Diagram by Breakwaters with an Opening (B/L= 2.0) for Smax = 10Wave directionWave direction
  • 83. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-60-Period ratio Diffraction coefficientPeriod ratio Diffraction coefficientFig. T - 4.5.7(e) Diffraction Diagram by Breakwaters with an Opening (B/L= 2.0) for Smax = 25Wave directionWave direction
  • 84. PART II DESIGN CONDITIONS-61-Period ratio Diffraction coefficientPeriod ratio Diffraction coefficientFig. T - 4.5.7(f) Diffraction Diagram by Breakwaters with an Opening (B/L= 2.0) for Smax = 75Wave directionWave direction
  • 85. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-62-Period ratio Diffraction coefficientPeriod ratio Diffraction coefficientFig. T - 4.5.7(g) Diffraction Diagram by Breakwaters with an Opening (B/L= 4.0) for Smax = 10Wave directionWave direction
  • 86. PART II DESIGN CONDITIONS-63-Period ratio Diffraction coefficientPeriod ratio Diffraction coefficientFig. T - 4.5.7(h) Diffraction Diagram by Breakwaters with an Opening (B/L= 4.0) for Smax = 25Wave directionWave direction
  • 87. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-64-Period ratio Diffraction coefficientPeriod ratio Diffraction coefficientFig. T - 4.5.7(i) Diffraction Diagram by Breakwaters with an Opening (B/L= 4.0) for Smax = 75Wave directionWave direction
  • 88. PART II DESIGN CONDITIONS-65-Period ratio Diffraction coefficientPeriod ratio Diffraction coefficientFig. T - 4.5.7(j) Diffraction Diagram by Breakwaters with an Opening (B/L= 8.0) for Smax = 10Wave directionWave direction
  • 89. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-66-Period ratio Diffraction coefficienteriod ratio Diffraction coefficientFig. T - 4.5.7(k) Diffraction Diagram by Breakwaters with an Opening (B/L= 8.0) for Smax = 25Wave directionWave direction
  • 90. PART II DESIGN CONDITIONS-67-Period ratio Diffraction coefficientPeriod ratio Diffraction coefficientFig. T - 4.5.7(llll) Diffraction Diagram by Breakwaters with an Opening (B/L= 8.0) for Smax = 75Wave directionWave direction
  • 91. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-68-(2) Treatment of Obliquely Incident WavesWhen waves are obliquely incident to a breakwater that contains an opening, it is advisable to obtain thediffraction diagram by means of a numerical calculation. When this is not possible, or when the diffractiondiagram is only required as a rough guideline, the following approximate method may be used instead.(a) Determining the axis of the diffracted waveWhen waves are obliquely incident to a breakwater that contains an opening, the direction q¢ of the axis of thediffracted waves (see Fig. T- 4.5.8) varies slightly from the direction of incidence q. Tables T- 4.5.1 (a) ~ (c)list the direction of the axis of the diffracted waves as a function of the aperture ratio B/L and the direction ofincidence. These tables are used to obtain the direction q¢ of the axis of the diffracted waves, and then thevirtual aperture ratio B¢/L corresponding to q¢ is obtained from the following equation:(4.5.11)Table T- 4.5.1 Angle of Axis of Diffracted Waveθ¢(a) Smax = 10(a) Smax = 25(a) Smax =75Note: Angle in the parentheses is the angle of deflection relative to the angle of incidenceFig. T- 4.5.8 Virtual Aperture B¢ and Angle of Axis of Diffracted Waveθ¢(b) Fitting of a diffraction diagramOut of the diffraction diagrams of normal incidence in Figs. T-4.5.7 (a) ~ (llll), the diffraction diagram that hasan aperture ratio nearly equal to the virtual aperture ratio is selected. This diffraction diagram is next rotateduntil the direction of incidence matches the direction of the axis of the diffracted waves as determined fromTable T- 4.5.1. The diffraction diagram is then copied and taken to be the diffraction diagram for obliquelyB/LAngle between breakwater and incident wave direction q15º 30º 45º 60º1.02.04.053º (38º)46º (31º)41º (26º)58º (28º)53º (23º)49º (19º)65º (20º)62º (17º)60º (15º)71º (11º)70º (10º)70º (10º)B/LAngle between breakwater and incident wave direction q15º 30º 45º 60º1.02.04.049º (34º)41º (26º)36º (21º)52º (22º)47º (17º)42º (12º)61º (16º)57º (12º)54º (9º)70º (10º)67º (7º)65º (5º)B/LAngle between breakwater and incident wave direction q15º 30º 45º 60º1.02.04.041º (26º)36º (21º)30º (15º)45º (15º)41º (11º)36º (6º)55º (10º)52º (7º)49º (4º)66º (6º)64º (4º)62º (2º)B¢ L¤ B L¤( ) q¢sin=Principal direction of incident wavePrincipal direction of diffracted wave
  • 92. PART II DESIGN CONDITIONS-69-incident waves. The errors in this approximate method are largest around the opening in the breakwater; interms of the diffraction coefficient, the maximum error may amount to around 0.1 in the absolute value.(3) Method for Determining Diffraction Coefficient in a HarborThe diffraction coefficient within a complex shape of harbor is generally estimated by numerical computationwith a computer. Diffraction calculation methods include Takayama’s method, which involves linear superposition of analytical solutions for detached breakwaters, and calculation methods that use the Green functions.(4) Directional Spreading MethodWhen the length of an island or the width of the entrance of a bay is at least ten times the wavelength of theincident waves, there will not be a large difference between the wave height estimate by the direct diffractioncalculation and the estimate using the amount of directional wave energy that arrives directly at the point ofinterest behind the island or in the bay; the latter is called the directional spreading method. However, if thepoint of interest is just behind an island or headland, the effects of diffracted waves will be large, and so thedirectional spreading method cannot be applied.(5) Studies Using Hydraulic Model ExperimentsThanks to improvements in multidirectional random wave generating devices, it is easy to reproduce waves thathave directional spreading in the laboratory nowadays, meaning that diffraction experiments can be carried outrelatively easily. When carrying out a model experiment, an opening in the harbor model is set up within theeffective wave making zone, and the wave height is simultaneously measured at a number of points within theharbor. The diffraction coefficient is obtained by dividing the significant wave height in the harbor by thesignificant wave height at the harbor entrance averaged over at least two observation points.[2] Combination of Diffraction and RefractionWhen carrying out diffraction calculations for waves in waters where the water depth varies greatly, waverefraction must also be considered.[Commentary](1) When the water depth within a harbor is made more-or-less uniform by say dredging (this is often the case withlarge harbors), the refraction of waves after diffraction can be ignored. In order to determine the wave height inthe harbor in this case, it is acceptable to first carry out a calculation considering only refraction and breakingfrom the deepwater wave hindcasting point to the harbor entrance. Next, a diffraction calculation for the areawithin the harbor is carried out, taking the incident wave height to be equal to the calculated wave height at theharbor entrance. In this case, the wave height at a point of interest within the harbor is expressed using thefollowing equation:H = Kd Kr Ks H0 (4.5.12)whereKd: diffraction coefficient at the point of interest within a harborKr: refraction coefficient at the harbor entranceKs: shoaling coefficient at the harbor entrance (see 4.5.5 Wave Shoaling)H0: deepwater wave heightThe energy balance equation method or the improved energy balance equation method in which a termrepresenting dissipation due to wave breaking is added is appropriate as the refraction calculation method for theopen sea. Takayama’s harbor calmness calculation method, whereby diffraction solutions for detachedbreakwaters are superimposed in order to obtain the change in the wave height of irregular waves within theharbor due to diffraction and reflection, can be used for the diffraction calculation for the area within the harbor,provided there are no complex topographic variations within the harbor.(2) When there are large variations in water depth even at places screened by a breakwater (this is often the casewith relatively small harbors and coastal areas), it is necessary to simultaneously consider both diffraction andrefraction within the harbor. If ignoring wave reflection and just investigating the approximate change in waveheight, it is possible to carry out refraction and diffraction calculations separately, and then estimate the changein wave height by multiplying together the refraction and diffraction coefficients obtained.Calculation methods that allow simultaneous consideration of refraction and diffraction of irregular wavesinclude a method that uses time-dependent mild-slope irregular wave equations, a method in which theBoussinesq equation is solved using the finite difference method 29), and the multicomponent coupling methodof Nadaoka et al. There are also literatures in which other calculation methods are explained.
  • 93. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-70-4.5.4 Wave Reflection[1] GeneralIn the design of port and harbor facilities, investigations shall be carried out onto the effects of reflectedwaves from neighboring structures on the facilities in question and also the effects of wave reflection fromthe facilities in question on neighboring areas.[Commentary]It is necessary to take note of the fact that waves reflected from port and harbor facilities can exercise a largeinfluence on the navigation of vessels and cargo handling. For example, waves reflected from vertical breakwaterscan cause disturbances in navigation channels, and multiple-reflected waves from quaywalls can cause agitationswithin harbors.[Technical Notes](1) Composition of Reflected Waves and Incident WavesThe wave height Hs when incident waves and waves reflected from a number of reflective boundaries coexist (atrain of incident waves and those of reflected waves from reflective boundaries are termed the “wave groups”)can be calculated using the following equation:(4.5.13)whereHs: significant wave height when all of the wave groups are taken togetherH1, H2, ¼Hn: significant wave heights of wave groupsNote however that, if the wave action varies with the wave direction, the differences in the wave directions ofvarious wave groups must be considered. The calculated wave height is valid for places that are at least about0.7 wavelengths away from a reflecting boundary.Regarding the diffraction and/or refraction of waves for which wave direction is an important factor, thesignificant wave height is determined separately for each wave group by carrying out whatever calculation isnecessary for that wave group, when the wave directions of various wave groups differ. Then the compositewave height is calculated by putting these significant wave heights into equation (4.5.13). An acceptablealternative is to determine the spectrum for each wave group, add these spectra together in order to calculate thespectral form when the wave groups coexist, and then perform direct diffraction and/or refraction calculationsusing this spectrum.(2) Composition of PeriodsThe significant wave height to be used in calculating the wave force when two wave groups of different periodsare superimposed may be determined by the energy composition method (i.e., equation (4.5.13)). The significantwave period T1/3 may be determined using the following equation 30):(4.5.14)where(4.5.15)(4.5.16)0.632 + 0.144ln RT : 0.1 ≦ RT < 0.80.6 : 0.8 ≦ RT < 1 (4.5.17)13.97 + 4.33ln RT : 0.1 ≦ RT < 0.410.0 : 0.4 ≦ RT < 1 (4.5.18)(4.5.19)(4.5.20)(H1/3)I, (H1/3)II : significant wave heights of wave groups I and II before superimposition, respectively (m)(T1/3)I, (T1/3)II : significant wave periods of wave groups I and II before superimposition, respectively (s)Note that, in the above equations, I is assigned to the wave group with the shorter period and Ⅱto that with thelonger period.Hs H 12H22 ¼ Hn2+ + +=T1 3¤ kH1 3¤( )I2H1 3¤( )II2+H1 3¤( )I2T1 3¤( )I2¤ H1 3¤( )II2T1 3¤( )II2¤+-------------------------------------------------------------------------------------------=k 1.0 a RH m¤( ) 0.121Aln RH m¤( )–+=a 0.08 RTln( )2 0.15 RTln–=mîíì=Aîíì=RH H1 3¤( )IH1 3¤( )II¤=RT T1 3¤( )IT1 3¤( )II¤=
  • 94. PART II DESIGN CONDITIONS-71-(3) Methods for Calculating the Effects of Reflected WavesCalculation methods for investigating the extent of the effects of waves reflected from a structure include thepoligonal island reflection method and a simple method by means of diffraction diagrams.(a) Poligonal island reflection methodIn this calculation method, the theoretical solution that shows the wave transformation around a single convexcorner is separated into three terms, representing the incident, the reflected and the scattered waves,respectively. The term for the scattered waves is progressively expanded to obtain an approximate equation, sothat the method can be applied to the case where there are a number of convex corners. When there are anumber of convex corners, it is assumed as a precondition that the lengths of the sides between convex cornersare at least five times the wavelength of the incident waves, so that the convex corners do not interfere witheach other. It is necessary to take heed of the fact that errors may become large if the sides are shorter thanthis. Since another assumption is made such that the water depth is uniform, the refraction of reflected wavescannot be calculated. In general, it is sufficient for practical purposes if the lengths of the sides betweenconvex corners are at least about three times the wavelength of the incident waves. This calculation methodcan also be applied to the reflection of irregular waves by means of superposing component waves. Althoughthe wave diffraction problems can also be analyzed with this calculation method, there will be large errors if itis applied to the diffraction of waves by thin structures such as breakwaters.(b) Simple method by means of diffraction diagramsExplanation is made for the example shown in Fig.T- 4.5.9. The wave height at a point A on the frontface of an upright detached breakwater is estimatedwhen waves are incident on the detached break-water at an angle a. Instead of the detached break-water, it is supposed that there are two semi-infinitevirtual breakwaters with an opening, such as shownwith dashed lines in Fig. T- 4.5.9. Next, one consid-ers the situation whereby waves are incident on thevirtual opening from both the wave direction of theincident waves and the direction symmetrical to thiswith respect to the detached breakwater (i.e., thedirection shown by the dashed arrow in Fig. T-4.5.9), and draws the diffraction diagram for theopening (dashed lines in Fig. T- 4.5.9). The range ofinfluence of the reflected waves is represented bymeans of the diffraction diagram for the virtualbreakwaters with the opening. Accordingly, supposing that the diffraction coefficient at point A is read off asbeing 0.68, then the wave height ratio with respect to the incident waves at point A is obtained by combiningthis value of 0.68 with a value of 1.0 representing the incident waves; since it is the energies that are added, thewave height ratio becomes . It should be noted, however, that this value of 1.21 representsthe mean value of the wave height ratio around the point A. It is not advisable to use this method for pointswithin 0.7 wavelengths of the detached breakwater, because the errors due to a phase coupling effect will belarge.For the case of wave reflection by a semi-infinite breakwater, the virtual breakwater also becomes a semi-infinite breakwater in the opposite direction, and so the diffraction diagram for a semi-infinite breakwater isused. When the reflection coefficient of the front face of the breakwater is less than 1.0 due to wave-absorbingwork for example, the diffraction coefficient should be multiplied by the reflection coefficient before beingused. For example, if the reflection coefficient of the detached breakwater is 0.4 in the previous example, thewave height ratio at the point A becomes .[2] Reflection CoefficientReflection coefficients shall be determined appropriately based on the results of field observations,hydraulic model experiments, and past data.[Technical Notes](1) Approximate Values for Reflection CoefficientIt is desirable to evaluate the value of reflection coefficient by means of field observations. However, when it isdifficult to carry out observation or when the structure in question has not yet been constructed, it is standard toestimate reflection coefficient by referring to the results of hydraulic model experiments. In this case, it isdesirable to use irregular waves as the test waves. The method by Goda et al. 31) may be used for the analysis ofirregular wave test data.Fig. T- 4.5.9 Sketch Showing the Effectof Reflected Waves1 0.682+ 1.21=1 0.4 0.68´( )2+ 1.04=
  • 95. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-72-The following is a list of approximate values for the reflection coefficients of several types of structures.Upright wall: 0.7 ~ 1.0(0.7 is for the case of a low crown with much overtopping)Submerged upright breakwater: 0.5 ~ 0.7Rubble mound: 0.3 ~ 0.6Precast wave-dissipating concrete blocks: 0.3 ~ 0.5Upright wave-absorbing structure: 0.3 ~ 0.6Natural beach: 0.05 ~ 0.2With the exception of the upright wall, the lower limits in the above ranges of reflection coefficient correspondto the case of steep waves and the upper limits to waves with low steepness. It should be noted, however, thatwith the upright wave-absorbing structure, the reflection coefficient varies with the wavelength, and the shapeand dimensions of the structure.[3] Transformation of Waves at Concave Corners, near the Heads of Breakwaters, and aroundDetached BreakwatersAround the concave corners of structures, near the heads of breakwaters, and around detachedbreakwaters, the wave height becomes larger than the normal value of standing waves owing to the effectsof diffraction and reflection. This increase in wave height shall be investigated thoroughly. Moreover, theirregularity of waves shall be considered in the analysis.[Technical Notes](1) Influence of Wave IrregularityWhen the wave height distribution near a concave corner or the head of a breakwater is calculated for regularwaves, a distributional form with large undulations is obtained. However, when wave irregularity is incorporatedinto the calculation, the undulated form of the distribution becomes smoothed out, excluding the region withinone wavelength of a concave corner, and the peak value of the wave height becomes smaller. Calculation usingregular waves thus overestimates the increase in the wave height around concave corners and the heads ofbreakwaters.(2) Graphs for Calculating Wave Height Distribution around a Concave CornerWave height distributions for irregular waves near a concave corner are shown in Fig. T- 4.5.10. This figureexhibits the form of the distribution of the maximum value of the wave height, as obtained from numericalcalculations for each principal wave direction. It has been assumed that waves are completely reflected by thebreakwater. In the diagram, Kd is the ratio of the wave height at the front face of the main breakwater to the waveheight of the incident waves. The irregular waves used in the calculation has a spectral form with Smax = 75,which implies a narrow directional spreading. The long dash-dot line in each graph shows the distribution of themaximum value of the wave height at each point as obtained using an approximate calculation. The length l1 isthat of the main breakwater, l2 is that of the wing breakwater, and b is the angle between the main breakwaterand the wing breakwater. This figure may be used to calculate the wave height distribution near a concavecorner. When it is not easy to use the calculation program, the approximate calculation method may be used.(3) Wave-Height-Reducing Effects of Wave-Absorbing WorkWhen a wave-absorbing work is installed in order to suppress the increase in wave height around a concavecorner and if the wave-absorbing work is such that the reflection coefficient of the breakwater becomes no morethan 0.4, it is quite acceptable to ignore the increase in wave height due to the presence of concave corner.However, this is only the case when the wave-absorbing work extends along the whole of the breakwater. If thebreakwater is long, one cannot expect the wave-absorbing work to be very effective unless it is installed alongthe entire length of the breakwater, because the effect of waves reflected from the wing breakwater extend evento places at a considerable distance away from the concave corner. The same can be said for the influence of themain breakwater on the wing breakwater.
  • 96. PART II DESIGN CONDITIONS-73-Fig. T- 4.5.10 Distribution of the Maximum Value of the Wave Height around Concave Corner 32)Computer methodApproximate solution methodComputer methodApproximate solution method
  • 97. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-74-(4) Increase in Wave Height at the Head of a BreakwaterNear the head of a semi-infinite breakwater or those ofbreakwaters at a harbor entrance (specifically within adistance of one wavelength from the head), wavesdiffracted by breakwaters exercise an effect of local waveheight increase over the normal standing wave heights.Because the wave height distribution has an undulatingform even at the back face of a breakwater, it is necessaryto take heed of the fact that the difference in water levelbetween the inside and the outside of the breakwatergives rise to a large wave force. Figure T- 4.5.11 showsan example of the results of a calculation of the waveforce ratio (i.e., the ratio of the wave force to that of astanding wave) near the head of a breakwater.(5) Increase in Wave Height around Detached BreakwaterAlong a detached breakwater, waves with the height greater than that of normal standing waves are produced,and the wave height distribution takes an undulating form even at the back face of the breakwater. This is due tothe effect of wave diffraction at the two ends of the breakwater 34). The wave force also becomes large due to thedifference between the water levels in the offshore and onshore sides of the breakwater. In particular, it isnecessary to take heed of the fact that, with a detached breakwater, the place where the maximum wave force isgenerated can shift greatly with the wave direction and the ratio of the breakwater length to the wavelength.Figure T- 4.5.12 shows an example of the results of a calculation of the wave force distribution along a detachedbreakwater for unidirectional irregular waves. In this calculation, the wave direction for which the largest waveforce occurrs is a = 30º (i.e., not when the waves are normally incident to the breakwater, but rather whenobliquely incident with a relatively shallow angle).Fig. T- 4.5.12 Wave Force Distribution along a Detached Breakwater4.5.5 Wave ShoalingWhen waves propagate into shallow waters, shoaling shall be considered in addition to refraction anddiffraction. It shall be standard to consider the nonlinearity of waves when calculating the shoalingcoefficient.[Commentary]Shoaling is one of the important factors that lead to changing of the wave height in coastal waters. It exemplifies thefact that the wave height in shallow waters is also governed by the water depth and the wave period. Figure T- 4.5.13has been drawn up based on Shuto’s nonlinear long wave theory. It includes the linearized solution by the smallamplitude wave theory and enables the estimation of the shoaling coefficient from deep to shallow waters. In thediagram, Ks is the shoaling coefficient, H0¢ is the equivalent deepwater wave height, H is the wave height at waterdepth h, and L0 is the wavelength in deepwater.Irregular wavesRegular wavesWaveforceratio0Fig. T- 4.5.11 Wave Force Distribution alonga Semi-Infinite Breakwater 33)WaveforceratioN (m)α=30°45°60°75°90°αN
  • 98. PART II DESIGN CONDITIONS-75-Fig. T- 4.5.13 Graph for Evaluation of Shoaling Coefficient4.5.6 Wave BreakingAt places where the water depth is no more than about three times the equivalent deepwater wave height,changing of the wave height due to wave breaking shall be considered. It shall be standard to consider theirregularity of waves when calculating the change in the wave height due to wave breaking.[Commentary]After the height of waves has increased owing to shoaling, waves break at a certain water depth and the wave heightdecreases rapidly. This phenomenon is called the wave breaking. It is an important factor to be considered whendetermining the wave conditions exercising on maritime structures. For regular waves, the place at which wavesbreak is always the same: this is referred to as the “wave breaking point”. For irregular waves, the location of wavebreaking depends on the height and period of individual waves, and wave breaking thus occurs over a certaindistance: this area is referred to as the “breaker zone”.[Technical Notes](1) Change in Wave Height Due to Wave BreakingThe change in wave height due to wave breaking may be determined using Figs. T- 4.5.14 (a) ~ (e) or Figs. T-4.5.15 (a) ~ (e). These figures show the change in wave height for irregular waves as calculated by Goda 35), 44)using a theoretical model of wave breaking. For the region to the right of the dash-dot line on each graph, thechange in wave height is calculated using the shoaling coefficient (see 4.5.5 Wave Shoaling). For the region tothe left of this dash-dot line, the change in wave height due to wave breaking dominates, and so the wave heightmust be determined using this graph. As for the bottom slope, it is appropriate to use the mean bottom slope overthe region where the water depth to equivalent deepwater wave height ratio h/H0¢ is in the range of 1.5 to 2.5.(2) Scope of Application of Graphs of Wave Height ChangeAt places where the water depth is no more than about one half of the equivalent deepwater wave height, a majorportion of wave energy is converted to the energy of oscillating flows rather than to that of water levelundulation. Therefore, when calculating the wave force acting on a structure in a very shallow water, it isdesirable to use the wave height at the place where the water depth is one half of the equivalent deepwater waveheight, if the facilities in question are highly important.2%decayline000 00 00
  • 99. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-76-2%decaylineBottom slope00 000h / H0Fig. T- 4.5.14 (a) Diagram of Significant WaveHeight in the Breaker Zonefor Bottom Slope of 1/102%decaylineBottom slope00000Fig. T- 4.5.14 (b) Diagram of Significant WaveHeight in the Breaker Zonefor Bottom Slope of 1/202%decaylineBottom slope000 00Fig. T- 4.5.14 (c) Diagram of Significant WaveHeight in the Breaker Zonefor Bottom Slope of 1/302%decaylineBottom slope000 00Fig. T- 4.5.14 (d) Diagram of Significant WaveHeight in the Breaker Zonefor Bottom Slope of 1/50
  • 100. PART II DESIGN CONDITIONS-77-2%decaylineBottom slope00 000Fig. T- 4.5.14 (e) Diagram of Significant WaveHeight in the Breaker Zonefor Bottom Slope of 1/1002%decaylineBottom slope00 00Fig. T- 4.5.15 (a) Diagram of Highest WaveHeight in the Breaker Zonefor Bottom Slope of 1/102%decaylineBottom slope00 00Fig. T- 4.5.15 (b) Diagram of Highes WaveHeight in the Breaker Zonefor Bottom Slope of 1/202%decaylineBottom slope00 00Fig. T- 4.5.15 (c) Diagram of Highest WaveHeight in the Breaker Zonefor Bottom Slope of 1/30
  • 101. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-78-(3) Approximate Calculation Formulas for Breaking Wave HeightCalculation of wave height changes based on a theoretical model for wave breaking generally requires use of acomputer. However, considering the variability of the phenomenon and the overall accuracy, it is acceptable tocalculate wave height changes using the following simple formula 35), 44):= (4.5.21)where(4.5.22)The shoaling coefficient Ks is determined using Fig. T- 4.5.13, the operators min{ } and max{ } take theminimum and maximum value of the mulitiple quantities within the braces, respectively, and tanq is the bottomslope.Similarly, an approximate calculation formula for the highest wave height Hmax is given as follows:(4.5.23)where(4.5.24)(4) Graph for Calculating Breaking Wave Height 35)If the maximum value (H1/3)peak of the significant wave height in the breaker zone is taken as representative ofthe breaking wave height, then the breaker index curve becomes as shown in Fig. T- 4.5.16. If the water depth(h1/3)peak at which the significant wave height is a maximum is taken as representative of the breaker depth, thenthe graph for calculating the breaker depth becomes as shown in Fig. T- 4.5.17.2%decaylineBottom slope00 00Fig. T- 4.5.15 (d) Diagram of Highest WaveHeight in the Breaker Zonefor Bottom Slope of 1/502%decaylineBottom slope00 00Fig. T- 4.5.15 (e) Diagram of Highest WaveHeight in the Breaker Zonefor Bottom Slope of 1/100H1 3¤KsH0¢ h L0¤ 0.2³min b0H0¢ b1h+( ) bmaxH0¢ KsH0¢, ,{ } h L0¤ 0.2<≧::{b0 0.028 H0¢ L0¤( ) 0.38– 20 qtan( )1.5[ ]exp=b1 0.52 4.2 qtan[ ]exp=bmax max 0.92 0.32 H0¢ L0¤( ) 0.29– 2.4 qtan[ ]exp,{ }=Hmax =1.8KsH0¢ h L0¤ 0.2³min b0H0¢ b1h+( ) bmaxH0¢ 1.8KsH0¢, ,{ } h L0¤ 0.2<≧* * *::{b0 0.052 H0¢ L0¤( ) 0.38– 20 qtan( )1.5[ ]exp=*b1 0.63 3.8 qtan[ ]exp=*bmax max 1.65 0.53 H0¢ L0¤( ) 0.29– 2.4 qtan[ ]exp,{ }=*6474864748
  • 102. PART II DESIGN CONDITIONS-79-(5) Breaking Wave Height Criterion for Regular WavesFigure T- 4.5.18 shows the breaking wave height criterion for regular waves. This figure can be used tocalculate the breaking wave height criterion in hydraulic model experiments using regular waves. The curves inthe graph can be approximated with the following equation:(4.5.25)where tanq denotes the bottom slope.Figure T- 4.5.18 shows the limiting wave height at the point of first wave breaking. At places where thewater is shallow, the water depth increases owing to the wave setup caused by wave breaking. When estimatingthe limiting wave height in the breaker zone, it is thus necessary to consider this increase in water level.Fig. T- 4.5.18 Breaking Wave Height Criterion for Regular Waves(6) Change in Wave Height at Reef CoastsAt reef coasts where shallow water and a flat sea bottom continue over a prolonged distance, the change in waveheight cannot be calculated directly using Figs. T- 4.5.14 and T- 4.5.15. Instead, the following empiricalequation may be used 36):(4.5.26)Note: (01/3) peak is the maximum valueof 01/3 in the breaker zoneBottomslope00 0Fig. T- 4.5.16 Diagram of Maximum Valueof the SignificantNote: (01/3) peak is the water depth atwhich 01/3 is a maximumin the breaker zoneBottomslope0 00Fig. T- 4.5.17 Diagram of Water Depth at whichthe Maximum Value of the SignificantWave Height OccursHbL0------ 0.17 1 1.5phL0------ 1 15 4 3¤ qtan+( )–î þí ýì üexp–=Bottom slope00HxH0¢-------- B AxH0¢--------è øæ ö–î þí ýì üexp ah h¥+H0¢----------------+=
  • 103. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-80-whereH0¢: equivalent deepwater wave heightHx: significant wave height at a distance x from the tip of the reefh: water depth over the reef: increase in the mean water level at a place sufficiently distant from the tip of the reefThe coefficients A and a are 0.05 and 0.33, respectively, according to the results of hydraulic modelexperiments. However, it is advisable to use the following values that have been obtained from the data of fieldobservations.The coefficient B corresponds to the bottom slope at the front of the reef. Using Fig. T- 4.5.14, it is obtainedfrom the significant wave height Hx = 0 at water depth h as follows.(4.5.28)The term (h+ )/H0¢ is given by(4.5.29)where b = 0.56. From the continuity of the mean water level at the tip of the reef (x = 0), C0 is given by(4.5.30)The term represents the rise in the mean water level at water depth h, which is controlled by the bottomslope in front of the reef and wave steepness (see 4.7.1 Wave Setup).The calculation method in the above has been derived under the assumption that the water depth h over thereef is small and waves break over the reef. It is thus not possible to apply the method when the water is deepand wave breaking does not occur.Considering the breaking wave height criterion of a solitary wave, the highest wave height Hmax, x at thedistance x from the tip of the reef may be obtained as follows.(4.5.31)where min{a, b} is the smaller value of a or b, and is the rise in the mean water level at the distance x and isgiven by the following equation:(4.5.32)4.6 Wave Runup, Overtopping, and Transmission4.6.1 Wave RunupWave runup shall be calculated appropriately by taking into account the configuration and location of theseawall and the sea bottom topgraphy.[Commentary]The phenomenon of wave runup is dependent upon a whole variety of factors, such as the wave characteristics, theconfiguration and location of the seawall, and the sea bottom topography; thus the runup height varies in a complexway. There are calculation diagrams and equations based on the results of past researches that may be used, althoughthey are applicable only under certain limited conditions. When the seawall and sea bottom are complex in form, it isadvisable to determine wave runup heights by carrying out hydraulic model experiments. When designing seawalls ofgently sloping type and the like, it is advisable to set the crown elevation of the seawall to be higher than the runupheight for regular waves. However, for irregular waves, depending on the wave height, overflow can occur, and soh¥A 0.089H0¢h h¥+---------------- 0.015+=(4.5.27)þïïïýïïïüa0.20 4m H0¢ 2m³>( )0.33 H0¢ 4m³( )îïíïì=BHx 0=H0¢-------------- ah h¥+H0¢----------------–=h¥h h¥+H0¢---------------- C0 138---ba2+è øæ ö¤=C0hx 0= h+H0¢-----------------------è øæ ö238---bHx 0=H0¢--------------è øæ ö2+=hx 0=Hmax x, min 0.78 h hx+( ) 1.8Hx,{ }=hxhx h+H0¢--------------- C038---bHxH0¢--------è øæ ö2–=
  • 104. PART II DESIGN CONDITIONS-81-ultimately the crown elevation and the form of the seawall are determined so as to make the quantity of overtopping(see 4.6.2 Wave Overtopping) no more than a certain permissible value.[Technical Notes]The following is the description of methods for calculating the runup height over smooth impermeable slopes:(1) Simple Cross Section“A simple cross section” refers to the case in which a seawall (including an upright wall) having a front slope ofan uniform gradient a is located at a certain place (of water depth h) on the sea bottom with an almost uniformgradient q.(a) Region of standing wavesTakada has proposed the following equation for determining the runup height when the water depth h at thefoot of the levee is in the range where standing waves exist (i.e., deeper than the depth at the breaker line). Hedealt with two cases separately; i.e., the case where wave breaking does not occur on the front slope and thecase where such wave breaking does occur.Firstly, according to Miche’s equation, the minimum angle of inclination of the slope ac for which wavebreaking does not occur is found as that satisfying the following condition:(4.6.1)Accordingly, when the angle of inclination of the slope is greater than ac, wave breaking does not occur overthe slope, in which case the runup height is given by the following equation:: (4.6.2)where H0¢ is the equivalent deepwater wave height, Ks is the shoaling coefficient, H1 is the wave height at thewater depth at the foot of the slope, hs is the crest elevation, and R is the runup height.Takada used the following equation for hs/H1,which assumes that there is good agreement between thevalue from Miche’s standing wave theory and experimental data.(4.6.3)When the angle of inclination of the slope is smaller than ac, wave breaking does occur on the front slope. Inthis case, it is assumed that the runup height is proportional to tan2/3a, leading to the following equation:Ks : (4.6.4)When the water depth is such that standing waves exist, the runup height can be calculated as above. Themaximum runup height occurs when a = ac, with the runup height decreasing both when the slope is moresteeply inclined than this and when it is more gently inclined.(b) Region where the water is shallower than the breaker depthTakada has given the runup height for regions where the water is sufficiently shallow for wave breaking tooccur as follows:(4.6.5)where R0 is the runup height on the levee body at the shoreline (h = 0).Based on the experimental results of Toyoshima et al., R0/H0¢ is given as follows:: Bottom slope 1/10: Bottom slope 1/20 (4.6.6): Bottom slope 1/30The term hR in equation (4.6.5) is the water depth at the foot of the levee for which the runup height becomeslargest. It is estimated using Fig. T- 4.6.1, which shows the runup height for a vertical wall. The term LR in thefigure is the wavelength at water depth hR, while Rmax is the maximum runup height for the region where thewater depth is such that standing waves exist (i.e., the runup height when h = hR).2acp---------2acsinp----------------H0¢L0--------=RH0¢--------p2a-------hsH1------ 1–+è øæ ö Ks= a ac>hs H1¤ 1 pH1L------ khcoth 134 2khsinh----------------------14 h2 khcos-----------------------–+è øæ ö×+=R H0¢¤p2ac---------hsH1------ 1–è øæ ö+î þí ýì ü=accotacot--------------è øæ ö2 3¤a ac<R H0¢¤ Rmax H0¢¤ R0 H0¢¤–( )hhR----- R0 H0¢¤+=0.18 H0¢ L0¤( ) 1 2¤–R H0¢¤îïíïì= 0.075 H0¢ L0¤( ) 1 2¤–0.046 H0¢ L0¤( ) 1 2¤–
  • 105. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-82-(2) Complex Cross SectionA “complex cross section” refers to the case wherethe sea bottom topography and the configuration andlocation of the seawall (on the whole) are as shown inFig. T- 4.6.2.(a) When the cross section can be considered to becomplex, the runup height of the seawall isobtained as follows (refer to Fig. T- 4.6.2) 37).① The wave breaking point B is determined fromthe deepwater wave characteristics.② Next, the runup height R is assumed and thepoint A is set at the maximum runup point. Then,the points A and B are joined by a straight line,and the gradient of this line yields the virtualgradient cota.③ The runup height for this virtual gradient iscalculated using Fig. T- 4.6.3, and the calculatedheight is compared with the initially assumedrunup height. If the two do not agree, then a newrunup height is assumed, and the estimation are repeated (i.e., the new runup height is used to give a newvirtual gradient and so on). This iterative process is repeated until convergence is achieved.④ The value so obtained is taken to be the runup height for the complex cross section in question.(b) When the results obtained from this method are compared with actual experimental results for a complex crosssection, it is generally found that there is good agreement between the two, with the error usually being nomore than 10%. However, if the bottom slope is too gentle, the agreement between the two becomes poor, andso this method should only be used when the bottom slope is steeper than 1/30.(c) Figure T- 4.6.4 shows experimental results obtained for a bottom slope of 1/70. This figure provides a usefulreference when estimating the runup height for a complex cross section with a gentle bottom slope.Fig. T- 4.6.2 Complex Cross Section and Virtual GradientFig. T- 4.6.3 Runup Height on a SlopeShoaling coefficient00000Fig. T- 4.6.1 Graph for Estimating hR for a Vertical WallVirtual gradientMaximum runup pointWave breaking pointActual cross section
  • 106. PART II DESIGN CONDITIONS-83-Fig. T- 4.6.4 Runup Height on a Seawall Located Closer to the Land than the Wave Breaking Point(3) Oblique Wave IncidenceFigure T- 4.6.5 shows the relationship between the incident angle coefficient Kb and the angle b. Here, b is theangle between the wave crest line of the incident waves and the centerline of the seawall, and the incident anglecoefficient Kb is the ratio of the runup height for angle b to the runup height when the waves are normallyincident (i.e., when b = 0). This figure can be used to estimate the effect of wave incident angle on the runupheight.(4) Effects of Wave-Absorbing WorkThe runup height can be significantly reduced when the front face of a seawall is completely covered with wave-dissipating concrete blocks. Figure T- 4.6.6 shows an example. However, the effect of the concrete blocksvaries greatly according to the way in which they are laid, and so in general it is advisable to determine the runupheight by means of hydraulic model experiments.(5) Estimation ErrorsIt is important to note that the curves for determining the runup height have been obtained by averagingexperimental data that show a large scatter. It should also be noted that actual wave runup will frequentlyexceeds the design crown height because of wave irregularity when the crown height of a seawall is designedagainst the significant waves, even if the scatter of the experimental data is not considered; in fact, in extremecases as many as about a half of the waves may exceed this height. Accordingly, the crown height of a seawallshould not be decided based purely on the runup height of regular waves; rather, it is necessary to giveconsideration to the quantity of overtopping (see 4.6.2 Wave Overtopping).Holland(Former)Russia0 0Fig. T- 4.6.5 Relationship between Wave IncidentAngle and Runup Height(Full Lines: Experimental Values byPublic Works Research Institute,Ministry of Construction)Surface covered with wave-dissipatingconcrete blocksSmooth surface00 0Fig. T- 4.6.6 Reduction in Runup HeightDue to Wave-Absorbing Work
  • 107. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-84-4.6.2 Wave OvertoppingFor structures for which the quantity of overtopping is an important design factor, the overtopping quantityshall be calculated by carrying out hydraulic model experiments or by using data from hydraulic modelexperiments carried out in the past. In this case, wave irregularity shall be considered.[Commentary]The “quantity of overtopping” is the total volume of overtopped water. The “rate of overtopping”, on the other hand,is the average volume of water overtopping in a unit time; it is obtained by dividing the quantity of overtopping bythe time duration of measurement. The quantity of overtopping and the rate of overtopping are generally expressedper unit width.If the quantity of overtopping is large, then not only there will be damage to the seawall body itself, but alsodamage by flooding to the roads, houses and/or port and harbor facilities behind the levee or seawall, despite that thelevee or seawall is intended to protect them. There is further a risk to users of water frontage amenity facilities thatthey may be drowned or injured. During design, it is necessary to make the quantity of overtopping no more than acertain permissible value that has been determined in line with the characteristics of structures and the situation withregard to their usage. Furthermore, when estimating the quantity of overtopping by means of experiments, it isdesirable to consider changes in tidal water level, i.e., to carry out experiments for different water levels.[Technical Notes](1) Diagrams for Calculating the Rate of Overtopping 38)For an upright or wave-absorbing seawall that has a simple form (i.e., that does not have anything like a toeprotection mound or a crown parapet), the rate of overtopping may be estimated using Figs. T- 4.6.7 ~ 4.6.10.These graphs have been drawn up based on experiments employing irregular waves. From the results of acomparison between the experiments and field observations, it is thought that the accuracy of the curves givingthe rate of overtopping is within the range listed in Table T- 4.6.1. The rate of overtopping for the wave-absorbing seawall has been obtained under the conditition that the lower armor layer at the crown consists of 2rows of wave-dissipating concrete blocks.Table T- 4.6.1 Estimated Range for the Actual Rate of Overtopping Relative to the Estimated ValueNote that when obtaining rough estimates for the rate of overtopping for irregular waves using Figs. T- 4.6.7 ~4.6.10, the following should be considered:(a) If the actual values of the bottom slope and the deepwater wave steepness do not match any of the values onthe graphs, the graph for which the values most closely match should be used, or alternatively interpolationshould be carried out.(b) The wave-dissipating concrete blocks in the figures are made up of two layers of tetrapods. If a different kindof wave-dissipating concrete block is used, or if the same kind of wave-dissipating concrete block is used butthere are differences in the crown width, in the way in which the tetrapods are laid, or in the form of the toe,then there is a risk that the actual rate of overtopping may considerably differ from the value obtained by thefigures.(c) If the number of rows of concrete blocks at the crown is increased, the quantity of overtopping tends todecrease 39).(d) When there are difficulties in applying the graphs for estimating the rate of overtopping, the approximateequation of Takayama et al. 40) may be used.Upright seawall Wave-absorbing seawall10-210-310-410-50.7 ~ 1.5 times0.4 ~ 20.2 ~ 30.1 ~ 50.5 ~ 2 times0.2 ~ 30.1 ~ 50.05 ~ 10q 2g H0( )3( )¤
  • 108. PART II DESIGN CONDITIONS-85-Fig. T- 4.6.7 Graphs for Estimating the Rate of Overtopping for an Upright Seawall (Bottom Slope 1/30)
  • 109. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-86-Fig. T- 4.6.8 Graphs for Estimating the Rate of Overtopping for an Upright Seawall (Bottom Slope 1/10)
  • 110. PART II DESIGN CONDITIONS-87-Fig. T- 4.6.9 Graphs for Estimating the Rate of Overtopping for a Wave-Absorbing Seawall (Bottom Slope 1/30)Concrete block00000000Concrete block0 0000000000Concrete block000 00000
  • 111. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-88-Fig. T- 4.6.10 Graphs for Estimating the Rate of Overtopping for a Wave-Absorbing Seawall (Bottom Slope 1/10)Concrete block0 000 00000Concrete block0 000000Concrete block0000000
  • 112. PART II DESIGN CONDITIONS-89-(2) Permissible Rate of OvertoppingThe permissible rate of overtopping depends on factors such as the structural type of the seawall, the situationwith regard to land usage behind the seawall, and the capacity of drainage facilities; it must be set appropriatelyin line with the individual situation. Although it is thus impossible to give one standard value for the permissiblerate of overtopping, Goda 41) nevertheless gave the values for the damage limit rate of overtopping as listed inTable T- 4.6.2 based on past cases of disasters. Furthermore, Nagai et al. have considered the degree ofimportance of the facilities behind the seawall and have come up with the values for the permissible rate ofovertopping as listed in Table T- 4.6.3, using the results of experiments with regular waves.Table T- 4.6.2 Damage Limit Rate of OvertoppingTable T- 4.6.3 Permissible Rate of Overtopping (m3/m•s) as a Function of the Degree of Importance of the Hinterland(3) Equivalent Crown Height CoefficientThe equivalent crown height coefficient can be used as a guideline when setting the quantity of overtopping fora seawall upon which wave-dissipating concrete blocks are laid or for a seawall of wave-absorbing type withvertical slits. The equivalent crown height coefficient is the ratio of the height of the seawall in question to theheight of an imaginary upright seawall that results in the same quantity of overtopping, where the conditions interms of waves and the sea bottom topography are taken to be the same for the both cases. If the equivalentcrown height coefficient is less than 1.0, this means that the crown of the seawall under study can be loweredbelow that of an upright seawall and still give the same quantity of overtopping; in other words, the seawallunder study has a form that is effective in reducing the quantity of overtopping. Below are the reference valuesfor the equivalent crown height coefficient b for typical types of seawall.Wave-absorbing seawall with concrete block mound 40): ~ 0.7Vertical-slit type seawall 40) :Parapet retreating type seawall 39) : ~ 0.5Stepped seawall 39) : ~ 1.0When the waves are obliquely incident 42) :(q is the angle of incidence of the waves; it is 0º whenthe waves are normally incident on the seawall)(4) Effect of Winds on the Quantity of OvertoppingIn general, winds have a relatively large effect on the quantity of overtopping when it is small, although there isa lot of variation. However, the relative effect of winds decreases as the quantity of overtopping increases.Figure T- 4.6.11 shows the results of an investigation on the wind effect on the quantity of overtopping based onfield observations. The abscissa shows the spatial gradient of the quantity of overtopping, while the ordinateshows the quantity of overtopping per unit area. As can be seen from the figure, when the quantity ofovertopping is small, the larger the wind velocity, the smaller the spatial gradient of the quantity of overtoppingbecomes. When the quantity of overtopping is large, the spatial gradient of the quantity of overtoppingincreases. This shows that, when the quantity of overtopping is small, the distance over which a mass of watersplash strongly affected by the wind velocity, with a larger distance at a higher wind velocity; however, when thequantity of overtopping is large, the difference in the splash distance becomes small.(5) Overtopping of Multidirectional Random WavesIn waters where the multidirectionality of waves is well clarified, the rate of overtopping may be corrected inline with Smax as in reference 42).Type Covering Rate of overtopping (m3/m•s)RevetmentApron pavedApron unpaved0.20.05LeveeConcrete on front slope, crown, and back slopeConcrete on front slope and crown, but no concrete on backslopeConcrete on front slope only0.050.020.005 or lessAreas where there is a high concentration of houses, public facilities etc.behind the seawall, and so it is anticipated that flooding due to overtopping orspray would cause particularly serious damageAbout 0.01Other important areas About 0.02Other areas 0.02 ~ 0.06b 0.9=b 0.6=b 1.0=b 1.7=bîíì=1 2qsin–1 2i30°sin–::q 30°£q 30°>≦þýü
  • 113. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-90-Fig. T- 4.6.11 Wind Effect on Spatial Gradient of Wave Overtopping Quantity4.6.3 Wave TransmissionIt shall be standard to calculate the height of waves transmitted behind a breakwater by overtopping and/orpermeation through the core or the fundation mound of breakwater by referring to either the results ofhydraulic model experiments or the past data.[Commentary]It is necessary to appropriately estimate the transmitted wave height after waves have overtopped and/or passedthrough a breakwater, because the transmitted waves affect the wave height distribution behind the breakwater.Transmitted waves include waves that have overtopped and/or overflowed, as well as waves that have permeatedthrough a rubble mound breakwater or a foundation mound of composite breakwater. Recently, several breakwatershave been built with caissons (which are originally not permeable) having through-holes in order to enhance theexchange of the seawater within a harbor. In this case, it is necessary to examine the value of wave transmissioncoefficient, because the coefficient serves as an indicator of the efficiency of the exchange of seawater.[Technical Notes](1) Transmission Coefficient for a Composite BreakwaterFigure T- 4.6.12 may be used to calculate the height of waves that are transmitted into a harbor when theyovertop a composite breakwater or permeate through a foundation mound. Even when the waves are irregular,the transmission coefficient agrees pretty well with that shown in Fig. T- 4.6.12. It has also been shown that Fig.T- 4.6.12 is valid not only for the significant wave height, but also for the highest one-tenth wave height and themean wave height.Fig. T- 4.6.12 Graph for Calculating the Wave Height Transmission CoefficientWindvelocityQuantityofovertoppingperunitareaqGradient
  • 114. PART II DESIGN CONDITIONS-91-(2) Period of Transmitted Waves for a Composite BreakwaterThe period of the transmitted waves drops to about 50 ~ 80% of the corresponding incident wave period (this istrue both for the significant wave period and the mean period).(3) Experimental Data on Other Types of BreakwaterFor composite breakwaters covered with wave-dissipating concrete blocks, rubble mound breakwaters armoredwith wave-dissipating concrete blocks, and other such breakwaters, experiments on the transmitted wave heighthave been carried out by the Civil Engineering Research Institute of Hokkaido Development Bureau.(4) Transmission Coefficient for Structures Other than Composite Breakwaters(a) For a porous, water-permeable structure such as a rubble mound breakwater or a wave-dissipating concreteblock type breakwater, Kondo’s theoretical analysis may be referred to. The following empirical equation maybe used to obtain the transmission coefficient of a typical structure.Stone breakwater: (4.6.7)where kt=1.26 (B/d)0.67, B is the crown width of the structure, d is the depth from the water surface to theground surface of the structure, H is the height of incident waves, and L is the wavelength of transmittedwaves.(b) For a curtain wall breakwater, the empirial solutions of Morihira et al. 43) may be used (see Part VII, 3.3.1Curtain Wall Breakwater).(c) For the transmission coefficient of an upright breakwater of permeable type that has slits in both the front andrear walls, the experimental results are available.(d) Types of breakwater aiming to promote the exchange of seawater include multiple-wing type permeablebreakwaters, multiple-vertical cylinder breakwaters, horizontal-plate type permeable breakwaters, and pipetype breakwaters. The transmission coefficients of these types of breakwater have been obtained by hydraulicmodel tests.(5) Transmission Coefficient for a Submerged BreakwaterA submerged breakwater is usually made by piling up natural stones or crushed rock to form a mound, and thencovering the surface with concrete blocks to protect underlayers. For a submerged breakwater of crushed rock, agraph showing the relationship between the crown height of the breakwater and the transmission coefficient isavailable.4.7 Wave Setup and Surf Beat4.7.1 Wave SetupWhen designing structures that will be placed within the breaker zone, it is desirable to consider thephenomenon of wave setup as necessary, which occurs in the breaker zone owing to wave breaking as theyapproach the coast.[Technical Notes](1) Diagrams for Estimating the Amount of Wave SetupThe changes in the mean water level by random wave breaking on the bottom slopes of 1/100 and 1/10 ascalculated by Goda 35), 44) are shown in Figs. T- 4.7.1 and T- 4.7.2. The smaller the wave steepness (H0¢/L0,where H0¢ is the equivalent deepwater wave height and L0 is the wavelength in deepwater ), the larger the rise ofmean water level becomes. Moreover, the steeper the bottom slope, the larger the rise of mean water level.Figure T- 4.7.3 shows the rise of mean water level at the shoreline. The effects of wave steepness and bottomslope on the rise of mean water level are clearly shown. When H0¢/L0 is in the range 0.01 ~ 0.05, with theexception of very steep bottom slope, the rise of mean water level near the shoreline is of the order (0.1 ~0.15)H0¢.(2) Consideration of the Rise in Mean Water Level in DesignA rise of mean water level causes the wave breaking point to shift shoreward and the breaking wave height toincrease. The rise of in mean water level is thus important for the accurate calculation of the design wave heightin shallow waters.KT 1 1 kt H L¤+( )¤=
  • 115. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-92-4.7.2 Surf BeatIn shallow waters, surf beat with the period of one to several minutes shall be investigated as necessary.[Technical Notes]Goda’s Formula for Estimating Surf Beat AmplitudeBased on the results of field observations of surf beat, Goda has proposed the following relationship 35), 44):(4.7.1)Changeinmeanwaterlevel0000/H0η′/H0h ′Fig. T- 4.7.1 Change in Mean Water Level(Bottom Slope 1/10)Changeinmeanwaterlevel000/H0h ′0η/H0′Fig. T- 4.7.2 Change in Mean Water Level(Bottom Slope 1/100)RiscinmeanwaterlevelWave steepness00 0Fig. T- 4.7.3 Rise in Mean Water Levelat the ShorelineOaraiNiigataMiyazakiNear shoreline Offshore0000zrmshrms( )0---------------------H0¢L0--------- 1hH0¢---------+è øæ ö1 2¤Fig. T- 4.7.4 Ratio of Surf Beat Amplitude toDeepwater Wave Amplitudezrms0.04 hrms( )0H0¢L0-------- 1hH0¢--------+è øæ ö-------------------------------------0.01H0¢H0¢L0-------- 1hH0¢--------+è øæ ö-------------------------------------= =
  • 116. PART II DESIGN CONDITIONS-93-where zrms is the root mean square amplitude of the surf beat wave profile, (hrms)0 is the root mean squareamplitude of the deepwater wave profile, H0¢ is the equivalent deepwater wave height, L0 is the wavelength indeepwater, and h is the water depth.This equation shows that the amplitude of the surf beat is proportional to the deepwater wave height, that itfalls as the water depth increases, and that it increases as the deepwater wave steepness H0¢/L0 decreases. FigureT- 4.7.5 shows a comparison between the estimation by equation (4.7.1) and actual observation values.4.8 Long-Period Waves and SeicheWith regard to long-period waves and seiche in harbors, field observations shall be carried out as far aspossible, and appropriate measures to control them shall be taken based on the results of theseobservations.[Commentary]Water level fluctuations with the period between one and several minutes sometimes appear at observation points inharbors and off the shore. Such fluctuations are called long-period waves. If the period of such long-period waves isclose to the natural period of oscillation of the vibration system made up of a vessel and its mooring ropes, thephenomenon of resonance can give rise to a large surge motion even if the wave height is small, resulting in largeeffects on the cargo handling efficiency of the port. If it is clear from observations that long-period waves ofsignificant wave height 10 ~ 15 cm or more frequently arise in a harbor, it is advisable to investigate either hard orsoft countermeasures.When conspicuous water level fluctuations with the period several minutes or longer occur at an observation pointin a harbor, it can be assumed that the phenomenon of “seiche” is taking place. This phenomenon occurs when smalldisturbances in water level generated by changes in air pressure out at sea are amplified by the resonant oscillationsof the harbor or bay. If the amplitude of such seiche becomes significantly large, inundation at the head of the bay orreverse outflow from municipal drainage channels may occur. Also high current velocities may occur locally in aharbor, resulting in breaking of the mooring ropes of small vessels. When drawing up a harbor plan, it is thusdesirable to give consideration to making the shape of the harbor to minimize the seiche motion as much as possible.[Technical Notes](1) Threshold Height of Long-period Waves for CargoHandling WorksIt is necessary to give due consideration to the factthat long-period waves in front of a quaywall caninduce ship surging with the amplitude of severalmeters through resonance. The threshold height oflong-period waves for smooth cargo handling worksdepends on the factors such as the period of the long-period waves, the dimensions of the vessel inquestion, the mooring situation, and the loadingconditions. Nevertheless, according to fieldobservations carried out in places like TomakomaiBay 46), it corresponds to a significant wave height ofabout 10 ~ 15 cm.(2) Calculating the Propagation of Long-period WavesIt is desirable to calculate the propagation of long-period waves into a harbor by setting up incidentwave boundary out at sea and then using either theBoussinesq equation 29) or a calculation method thatuses long linear wave equations 47).(3) Standard Spectrum for Long-period WavesWhen there has been insufficient field observationdata of long-period waves out at sea and the long-period wave conditions that determine the design external forces have not been established, the standardspectrum shown in reference 48) or its approximate expression may be used. Figure T- 4.8.1 shows a comparisonbetween an observed spectrum and an approximate form of the standard spectrum. The term al in the figure is aparameter that represents the energy level of the long-period waves.(4) Calculation Method for SeicheSee 6.5 Seiche for a calculation method for seiche.Observed spectrumApproximate form ofstandard spectrumFig. T- 4.8.1 Comparison between Standard Spectrumwith Long-period Components andObserved Spectrum
  • 117. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-94-4.9 Waves inside Harbors4.9.1 Calmness and DisturbancesWhen evaluating the harbor calmness, the factors that give rise to disturbances in the harbor shall be setappropriately.[Commentary]The problem of harbor calmness is extremely complex. It involves not only physical factors such as waves, winds,vessel motions, and the wind- and wave-resistance of working machinery, but also the factors requiring humanjudgement: the latter include the easiness of vessels entering and leaving a harbor, vessel refuge during stormyweather, and the threshold conditions of works at sea. The harbor calmness is further related with the economicfactors, such as the efficiency of cargo handling works, the operating rate of vessels, and the cost of constructing thevarious facilities required to improve the harbor calmness. The factors that lead to wave disturbances in harbors,which form the basis of the criteria for determining the harbor calmness, include the following:(a) Waves penetrating through the harbor entrance(b) Transmission of waves into the harbor over breakwaters(c) Reflected waves(d) Long-period waves(e) SeicheIn large harbors, wind waves generated within the harbor may require attention, and the ship-generated waves bylarger vessels may cause troubles for small vessels.4.9.2 Evaluation of Harbor CalmnessThe harbor calmness shall be evaluated by considering individual wave components estimated separatelyfor respective factors that cause disturbances in the harbor.[Technical Notes]The following method may be used for evaluating the harbor calmness:(1) To estimate the waves in the harbor, first establish the joint distribution of the height and direction of deepwaterwaves.(2) Next, calculate the wave transformations by refraction and breaking that takes place between the deepwaterwave observation and/or hindcasting point and the harbor entrance, using say the energy balance equationmethod, and thus obtain the wave conditions at the harbor entrance.(3) Obtain the wave height in the harbor, focusing mainly on diffraction and reflection. If necessary, carry out aninvestigation on wave transmission at this time.(4) The wave height in the harbor can be estimated by taking the squares of each of the diffracted wave height, thereflected wave height and the transmitted wave height, adding the results, and then taking the square root. Forharbors where the effects of transmitted waves are relatively slight, the wave period in the harbor may be takento be the same as the period of the diffracted waves. Note that the wave height in the harbor should beinvestigated for each wave direction for various classes of wave heights with the occurrence probability outsidethe harbor.(5) It is standard to express the occurrence rate of waves in a harbor as the percentage of the waves exceeding 0.5 mor 1.0 m in height or in terms of the number of days. However, depending on the usage purpose, it is alsoacceptable to take into consideration the exceedance probability for other wave height classes. The harborcalmness is obtained by subtracting from 100% the occurrence probability (in percentage) that the wave heightin the harbor exceeds the threshold level for cargo handling works at the berth in question. It is not possible todetermine a value for the threshold wave height for cargo handling works that is valid universally; rather, itdepends on the purpose for which the wharf facilities are used, the dimensions of vessels, and the period anddirection of waves, etc. Nevertheless, a value of 0.5 to 1.0 m (significant wave height) may be used as areference value. However, it should be noted that the critical wave height for cargo handling is lower for wavesof long-periodicity such as swell 49), and so care is required when evaluating the net working rate for ports andharbors that face out onto the open sea.4.10 Ship WavesIn canals and navigation channels, it is desirable to examine the influence of waves generated by movingvessels.
  • 118. PART II DESIGN CONDITIONS-95-[Technical Notes](1) Pattern of Ship Waves as Viewed from TopIf ship waves are viewed from top, it appears as shown in Fig. T- 4.10.1. Specifically, it is composed of twogroups of waves. One group of waves spread out in a shape like 八 (the Chinese character for 8) from a pointslightly ahead of the bow of the vessel. The other group of waves are behind the vessel and are such that thewave crest is perpendicular to the vessel’s sailing line. The former waves are termed the “divergent waves”,while the latter are termed the “transverse waves”. The divergent waves form concave curves; the closer to thesailing line, the smaller the gap between waves. On the other hand, the transverse waves are approximately arc-shaped, with the gap between waves being constant (i.e., independent of the distance from the sailing line). Indeep water, the area over which the ship waves extend is limited within the area bounded by the two cusplineswith the angles ± 19º28 from the sailing line and starting from the origin (i.e., the point from which the cusplines diverge) lying somewhat in front of the bow of the vessel. The divergent waves cross the transverse wavesjust inside the cusplines; this is where the wave height is largest. The wave steepness is smaller for the transversewaves than for the divergent waves, implying that the transverse waves often cannot be discerned from an aerialphotograph.Fig. T- 4.10.1 Plan View of Ship Waves(2) Wavelength and Period of Ship WavesThe wavelength and period of ship waves differ for the divergent waves and the transverse waves, with the latterhaving both a longer wavelength and a longer period. Amongst the divergent waves, the wavelength and periodare both longest for the first wave and then become progressively shorter.(a) The wavelength of the transverse waves can be obtained by the numerical solution of the following equation,which is derived from the condition that the celerity of the transverse waves must be the same as the velocityat which the vessel is sailing forward.: (provided ) (4.10.1)whereLt: wavelength of transverse waves (m)h: water depth (m)V: sailing speed of vessel (m/s)Note however that when the water is sufficiently deep, the wavelength of the transverse waves is given by thefollowing equation:(4.10.2)whereL0: wavelength of transverse waves at places where the water is sufficiently deep (m)Vk: sailing speed of vessel (kt); Vk = 1.946V (m/s)(b) The period of the transverse waves is equal to the period of progresseive waves with the wavelength Lt (or L0)in water of depth h. It is given by equation (4.10.3) or (4.10.4).(4.10.3)(4.10.4)Vessels sailing linegLt2p------- 2phLt----------tanh V 2= V gh<L02pg------V 2 0.169Vk2= =Tt2pg------Lt2phLt----------è øæ öcoth T02phLt----------è øæ öcoth= =T02pg------V 0.330Vk= =
  • 119. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-96-whereTt: period of transverse waves in water of depth h (s)T0: period of transverse waves at places where the water is sufficiently deep (s)(c) The wavelength and period of the divergent waves are given by equations (4.10.5) and (4.10.6), which arederived from the condition that the component of the vessel’s speed in the direction of travel of the divergentwaves must be equal to the velocity of the divergent waves.(4.10.5)(4.10.6)whereLd: wavelength of divergent waves as measured in the direction of travel (m)Td: period of divergent waves (s)q: angle between the direction of travel of the divergent waves and the sailing line (º)According to Kelvin’s theory of wave generation at places where the water is sufficiently deep, the angle oftravel q of the divergent waves can be obtained as shown in Fig. T- 4.10.2, as a function of the position of theplace under study relative to the vessel. Note however that for actual vessels the minimum value of q isgenerally about 40º, and q is usually about 50º ~ 55º for the point on a particular divergent wave at which thewave height is a maximum. Note also that, as shown in the illustration in the figure, the angle q directs thelocation of the source point Q from where the divergent wave has been generated; a is the angle between thecusp line and the sailing line.Fig. T- 4.10.2 Wave Direction and Period ofat Places Where the Water is Sufficiently Deep(3) Shoaling Effect on Ship WavesAs common with water waves in general, ship waves are affected by the water depth, and their properties varywhen the water depth decreases relative to the wavelength of ship waves. This shoaling effect on ship wavesmay be ignored if the following condition is satisfied:V ≦ (4.10.7)The critical water depth above which ship waves may be regarded as deepwater waves is calculated by equation(4.10.7), as listed in Table T-4.10.1. As can be seen from this table, the waves generated by vessels in normalconditions can generally be regarded as deepwater waves. Situations in which they must be regarded as shallowwater waves include the following cases: a high-speed ferry travels through relatively shallow waters, amotorboat travels through shallow waters, and ship waves propagate into shallow waters. Note that ship wavesin shallow water have a longer wavelength and period than those generated by the vessel sailing in deep water atthe same speed.Ld Lt2qcos=Td Tt qcos=RatiooftheperiodofthedivergentwavestothatofthetransversewavesTd/T0AnglebetweenthedirectionoftravelofthedivergentwavesandthesailinglineGRelative position of observation point x / s000.7 gh
  • 120. PART II DESIGN CONDITIONS-97-Table T-4.10.1 Conditions under Which Ship Waves Can Be Regarded as Deepwater Waves(4) Height of Ship WavesThe Ship Wave Research Committee of the Japan Association for Preventing Maritime Accidents has proposedthe following equation for giving a rough estimate of the height of ship waves:(4.10.8)whereH0: characteristic wave height of ship waves (m), or the maximum wave height observed at a distance of100 m from the sailing line when a vessel is sailing at its full-load cruising speedLs: length of the vessel (m): full-load cruising speed (kt)EHPW: wave-making power (W)The wave-making power EHPW is calculated as follows.(4.10.9)(4.10.10)(4.10.11)S ≒ (4.10.12)(4.10.13)whereSHPm: continuous maximum shaft power (W)r0: density of seawater (kg/m3); r0 = 1030 (kg/m3)V0: full-load cruising speed (m/s); V0 = 0.514VKCF: frictional resistance coefficientn: coefficient of kinematic viscosity of water (m2/s); n ≒ 1.2 × 10-6 (m2/s)Ñ: full-load displacement of vessel (m3)Equation (4.10.8) has been obtained by assuming that the energy consumed through wave making resistance isequal to the propagation energy of ship waves, while the values of the coefficients have been determined asaverages from the data from ship towing tank tests. The characteristic wave height H0 varies from vessel tovessel, although for medium-sized and large vessels it is about 1.0 ~ 2.0 m. Tugboats sailing at full speedproduce relatively large waves.It is considered that the wave height decays as s-1/3, where s is the distance of the observation point from thesailing line. It is also considered that the wave height is proportional to the cube of the cruising speed of thevessel. Accordingly:(4.10.14)whereHmax:maximum height of ship waves at any chosen observation point (m)s:distance from the observation point to the sailing line (m)Vk:actual cruising speed of the vessel (kt)Equation (4.10.14) cannot be applied if s is too small; specifically, the approximate minimum value of s forwhich equation (4.10.14) can be applied is either the vessel length Ls or 100 m, whichever is the smaller.The upper limit of the height of ship waves occurs when the breaking criterion is satisfied; this criterion isexpresed as the steepness Hmax/Lt of the highest divergent wave being equal to 0.14. If the angle between thewave direction and the sailing line is assumed to be q = 50º at the point on a divergent wave where the waveheight becomes largest, the upper limit of the wave height at any given point is given by equation (4.10.15). Thisalso assumes, however, that the conditions for deepwater waves are satisfied.(4.10.15)whereSpeed of vessel Vk (kt)Water depth h (m) ≧Period of transverse waves T0 (s)5.01.41.77.53.12.510.05.53.312.58.64.115.012.45.017.516.95.820.022.06.625.034.48.330.049.69.9H0Ls100---------è øæ ö1 3¤ EHPW1620LsVK------------------------=VKEHPW EHP EHPF–=EHP 0.6SHPm=EHPF12---rSV03CF=2.5 ÑLsCF 0.075V0Lsn-----------log 2–è øæ ö2¤=Hmax H0100s---------è øæ ö1 3¤ VkVK------è øæ ö3=Hlimit 0.010Vk2=
  • 121. TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN-98-Hlimit:upper limit of the height of ship waves as determined by the wave breaking conditions (m)(5) Propagation of Ship Waves(a) Among two groups of ship waves, the transverse waves propagate in the direction of vessel’s sailing line, andcontinue to propagate even if the vessel changes course or stops. In this case, the waves have a typical natureof regular waves (with the period being given by equation (4.10.3), and they propagate at the group velocity,undergoing transformation such as refraction and others. Takeuchi and Nanasawa gave an example of suchtransformations. Note however that as the waves propagate, the length of wave crest spreads out (the wavecrest gets longer), and even when the water is of uniform depth, the wave height decays in a manner inverselyproportional to the square root of the distance traveled.(b) The direction of propagation of a divergent wave varies from point to point on the wave crest. According toKelvin’s theory of wave generation, the angle between the direction of propagation and the sailing line is q =35.3º at the outer edge of a divergent wave. As one moves inwards along the wave crest, the value of qapproaches 90º. The first(c) arriving at a any particular point has the angle q = 35.3º, while q getting gradually larger for subsequentwaves. This spatial change in the direction of propagation of the divergent waves can be estimated using Fig.T- 4.10.2.(d) The propagation velocity of a divergent wave at any point on the wave crest is the group velocitycorresponding to the period Td at that point (see equation (4.10.6)). In the illustration in Fig. T- 4.10.2, thetime needed for a component wave to propagate at the group velocity from the point Q at wave source to thepoint P is equal to the time taken for the vessel to travel at the speed V from the point Q to the point O. Sinceeach wave profile propagates at the wave velocity (phase velocity), the waves appear to pass beyond thecuspline and vanish one after the other at the outer edge of the divergent waves.(6) Generation of Solitary Waves.When a vessel sails through shallow waters, solitary waves are generated in front of the vessel if the cruisingspeed Vk (m/s) approaches . Around the mouths of rivers, there is a possibility of small vessels beingaffected by such solitary waves generated by other large vessels 50).[References]1) Dean, G. R.: “Stream function wave theory and application”, Handbook of Coastal and Ocean Engineering, Volume 1, GulfPub., 1991, pp. 63-94.2) Dean G. R. and R. A. Dalrymple: “Water Wave Mechanics for Engineers and Scientists”, World Scientific, 1991, pp. 305-3093) Goda, Y.: “Wave forces on a vertical circular cylinder: Experiments and proposed method of wave force computation”, Rept.of PHRI, No. 8, 1964, 74 p.4) Yoshimi GODA, Yasumasa SUZUKI: “Computation of refraction and diffraction of sea waves with Mitsuyasu’s directionalspectrum”, Tech. Note of PHRI, No. 230, 1975 (in Japanese).5) Pierson, W. J. Jr., G. Neumann and R. W. James: “Practical methods for observing and forecasting ocean waves by means ofwave spectra and statistics”, U. S. Navy Hydrographic Office, Pub. No. 603, 1955.6) Inoue, T.: “On the growth of the spectra of a wind gererated sea according to a modified Miles-Phillips mechanism and itsapplication to wave forecasting”, Geophysical Science Lab., TR-67-5, New York Univ., 1967, pp. 1-74.7) Isozaki, I. and T. Uji: “Numerical prediction of ocean wind waves”, Papers of Meteorology and Geophysics, Vol. 24 No. 2,1973, pp. 207-231.8) Joseph, P. S., S. Kawai and Y. Toba: “Ocean wave prediction by a hybrid model combination of single-parameterized windwaves with spectrally treated swells”, Sci. Rept. Tohoku Univ., Ser. 5, (Tohoku Geophys. Jour.), Vol. 28, No. 1, 1981.9) Uji, T.: “A coupled discrete wave model MRI-II