Robert W. Fairbanks and Richard N. St. Jean, Coastal Shoreline Protection Using Hard Structures
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Robert W. Fairbanks and Richard N. St. Jean, Coastal Shoreline Protection Using Hard Structures

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BeachSAMP Stakeholder Meeting ...

BeachSAMP Stakeholder Meeting
December 9th, 2013
Robert W. Fairbanks, P.E., President
Fairbanks Engineering Corp.
Richard N. St. Jean, P.E., President
St. Jean Engineering, LLC

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Robert W. Fairbanks and Richard N. St. Jean, Coastal Shoreline Protection Using Hard Structures Robert W. Fairbanks and Richard N. St. Jean, Coastal Shoreline Protection Using Hard Structures Presentation Transcript

  • COASTAL SHORELINE PROTECTION USING HARD STRUCTURES Robert W. Fairbanks, P.E., President Fairbanks Engineering Corp. Richard N. St. Jean, P.E., President St. Jean Engineering, LLC
  • TYPES OF SHORELINE PROTECTION STRUCTURES • NON STRUCTURAL PROTECTION • SEAWALLS • REVETMENT • BREAKWATERS • GROINS
  • EXAMPLES OF MANMADE CHANGES TO THE SHORELINE IN RHODE ISLAND USING SEAWALLS, REVETMENTS, BREAKWATERS AND GROINS
  • Quonset Point War Effort Quonset Point 1939 Before World War II Quonset Point Today
  • Allen Harbor, North Kingstown Allen Harbor Pre World War II Effort Allen Harbor Today
  • Quonochontaug Breachway • 1952 Before State of RI Constructed Breachway • 1981 Aerial showing Breachway Constructed in 1962, and Sediment Entering Pond
  • Quonochontaug Pond • Quonochontaug Today with No Maintenance
  • Buttonwoods Warwick, RI • 1962 Timber and Stone Groins Showing Sand Accretion • Timber Groins Not Maintained Showing Loss of Accreted Sand
  • Buttonwoods, Warwick RI Section Where Stone Groins Remain
  • Non Structural Shoreline Protection Vegetated Beach Dune – Portsmouth, RI
  • Vegetated Shoreline • Portsmouth, Rhode Island
  • Portsmouth Shoreline Before Concrete Curbs
  • Jamestown, Rhode Island Coir Logs
  • Middletown, Rhode Island Coir Logs on Rocky Shoreline
  • SEAWALLS Steel Sheetpile Bulkhead, Road Town, BVI
  • Sheet Pile Dead Men Installation Road Town, Tortola, BVI
  • Concrete Seawall, Hampton Beach, NH
  • Salisbury Beach, Massachusetts Pre-Cast Concrete Seawall Units
  • Salisbury Beach, Massachusetts Precast Concrete Units
  • Re-Entrant Face Seawall, San Francisco
  • Concrete Seawall, Westerly, RI
  • Timber Seawall – Portsmouth, RI
  • Steel Sheet Piles, Quonset Airport
  • REVETMENTS • Stone placed on an earth slope, Warwick, RI
  • Revetment Under Construction, Jamestown, RI
  • Larger Revetment, Portsmouth, RI
  • Revetment Above Seawall, Westerly, RI
  • Revetment Above Seawall, Westerly, RI
  • STONE BREAKWATERS SAUNDERSTOWN YACHT CLUB Location of Former North Kingstown To Jamestown Ferry Landing – circa 1900
  • Shoreline Adjacent to SYC Breakwater North of Breakwater High Energy as Shown by Rocky Shore South of Breakwater High Energy as Shown by Rocky Shore
  • Beach Formed On South Side of SYC Breakwater Breakwater Acting As a Groin, Trapping Sand
  • GROINS Purpose is to trap sand to create a beach Buttonwoods, Warwick, RI
  • Remnants of Groins in Buttonwoods
  • Typical Groins Along Lake Michigan Groins Typically Interrupt & Trap Sand Moving Down the Coast Replenishing Beaches but Starve Down Shore Beaches Leading to More Aggressive Erosion. Tee Type Groin Standard Groin
  • SHORELINE PROTECTION • These structures have a place • Many coastal shoreline areas have been protected adequately by these structures across the country • Ports require deep water at dock faces • Ports require protection from waves to allow cargo to be loaded and unloaded • Municipalities need to protect infrastructure • Homeowners need to protect property – However these structures typically protect the shoreline better than they protect the structures behind
  • Non Structural Measures Pros: Environmentally Friendly Relatively Inexpensive to Construct and Maintain if Vegetative Blends into Natural Shoreline and Provides Essential Habitat Typically Does not Cause Erosion of Adjacent Properties Preferred Method in Low Energy Locations (Coves, Protected Areas) Easy to Permit Non Structural Measures Cons: Ineffective for Large Fetch Areas Where Waves are in Excess of Approx. 2 Feet Required Frequent Maintenance After Storm Events Requires a Large Footprint Perpendicular to the Shore
  • Seawalls Pros: Can Provide Deep Water Adjacent to Quay Walls, Ports Piers Small Footprint Seaward, Providing Additional Room for Navigation Excellent Earth Retention with Little to No Loss of Soil Behind Wall When Maintained When Properly Designed Can Sustain High Surcharge Loads at Piers and Adjacent Railways Can Incorporate Cleats, Bollards and Mooring Bits for Docking Seawall Cons: Large Wave Reflection Which Can Almost Double the Incoming Wave Height If Wave Phases Line Up Causing Damage to Marina Facilities Can Cause Excessive Erosion At Beginning and Ends of Wall Costly to Construct Short Life if not Properly Maintained (30 to 50 years) Possibly Shorter Life if in a Marina Environment Due to Stray Electric Current Permitted in Only Certain Water Types
  • Breakwater Pros: Provides Excellent Energy Absorption with Little Wave Reflection Durable If Properly Designed With Adequate Stone Sizes & Geometry Provides Fish and Sea Creature Habitat Long Lasting if Properly Designed with Durable Stones Ideal for Creating a Refuge Area for Port Facilities and Quiet Water for Pier Operations Breakwater Cons: Very Costly to Construct and Maintain Upsets Natural Circulation and Sediment Patterns Possibly for Long Distances Covers a Large Footprint at the Mud Line Requires Frequent Dredging At Harbor Entrances and Within Basin  Navigation Hazard if Not Properly Marked Very Difficult to Permit
  • DESIGN PARAMETERS • 100 Year (1%) Storm Generated Forces (FEMA) – Wave Height – Current Velocity – Debris Loads • Water Depth (Bathymetric Survey) • Shoreline Profile
  • DESIGN WAVE HEIGHT • FEMA Flood Study & FIRM MAP • Case By Case Study Considering Unobstructed Fetch (Partially or Fully Developed Seas) and Water Depth Approaching Structure Location Typical Design Parameters for Critical Structures – 100 yr Return (1%) Stillwater Elevation (SWL) – 100 yr Return (1%) Maximum Wave Crest Elevation (May Use a More Frequent Storm Event for Structures That Can Sustain Some Damage Without Loss of Life, Can be Readily Repaired, and Small Economic Impact)
  • DESIGN WAVE HEIGHT • Significant Wave Height, Hs – Hs = (Max Wave Crest El – SWL) /0.7 • Example for Max Wave Crest El = 12.0 ft & SWL = 9.0 ft • Hs = 12.0 ft – 9.0 ft/0.7 = 4.28 ft • Design for H10 = 1.27 Hs
  • EFFECT OF WAVE HEIGHT • Forces on vertical walls1 – 4 ft wave = 8000 lbs/lf – 8 ft wave = 16,000 lbs/lf – 12 ft wave = 24,000 lbs/lf 1 – Coastal Construction Manual, Figure 11-8
  • EFFECT OF WAVE HEIGHT • Forces & increased wave height at vertical walls
  • EFFECT OF WAVE HEIGHT • Revetment stone size2 – W = (Wr)(H3)/Kd(Sr – 1)3 (Cotan >) • Stone size required for 1.5H: 1.0V slope; 2 stone armor layer – – – – 4 ft wave = 2200 lbs (2.4 ft stone) 8 ft wave= 18,000 lbs (4.8 ft stone) 12 ft wave = 60,000 lbs (7 ft stone) 16 ft wave = 142,000 lbs (9.5 ft stone) 2 – US Army Corps of Engineers, Shore Protection Manual, 1984
  • EFFECT OF WAVE HEIGHT • Typical breakwater section2 2 – US Army Corps of Engineers, Shore Protection Manual, 1984
  • RI SHORELINE PROJECTS • Block Island’s Old Harbor Sheetpile Bulkhead – PZC-34 steel sheets; 41 ft long – Bulkhead length is 242 lf – Cost $732,000 or $3,025/lf
  • RI SHORELINE PROJECTS • Matunuck Beach Road Bulkhead & Revetment, South Kingstown – 202 lf of PZ-35 steel sheetpile (45 ft long sheets) – 202 lf of 11 ton armor stone (2 layers) – Cost $1,000,000 or $4,950/lf
  • CARRIBEAN SHORELINE PROJECTS • Tender Pier Anchored Bulkhead Road Town, Tortola, BVI – 331 lf of PZ-27 Steel Sheetpile (36 ft long sheets) – Buried Concrete Deadman w/ Steel Tie-rods – Cost $1,200,000 or $3,625/lf
  • RI SHORELINE PROJECTS • Larkin Road Seawall, Watch Hill – 185 lf of Concrete Seawall (17 ft high) – 18” -30” thick stem & 9 ft wide footing – Cost $500,000 or $2,700/lf
  • RI SHORELINE PROJECTS • Whipple Ave Revetment, Warwick – 100 lf of stone revetment – 5000 to 8000 lb stone, 2 stone armor layer – Cost $25,000 or $250/lf
  • RI SHORELINE PROJECTS • 75 Surfside Ave, Charlestown – 150 lf of stone revetment – 12000 lb stone, 2 stone armor layer – Cost $150,000 or $1,000/lf
  • RI SHORELINE PROJECTS • 89 Surfside Ave, Charlestown – 70 lf of stone revetment – 12000 lb stone, 2 stone armor layer – Cost $93,000 or $1,330/lf
  • RI SHORELINE PROJECTS • Baker Road, Portsmouth – 90 lf of stone revetment – 8000 lb stone, 2 stone armor layer – Estimated Cost $90,000 Or $1,000/lf
  • RI SHORELINE PROJECTS • Watch Hill Lighthouse Revetment, Watch Hill – 1,700 lf+- of existing stone revetment repairs – 20,000 lb stones or larger – 22 ft design wave heights – Estimated Cost N/A
  • RI SHORELINE PROJECTS • Larkin Ave Groin, Watch Hill – 150 lf+- of existing stone groin repairs – 3,000 to 4,000 lb stones – Estimated Cost $25,000+- or $170+-/lf
  • CARRIBEAN SHORELINE PROJECTS • Tender & Ferry Pier Breakwater Road Town, Tortola, BVI – 200 lf stone breakwater – 6,000 to 8,000 lb stones (2 stone armor layer) – Estimated Cost $620,000 or $3,100/lf
  • Examples of Programs Used for Design
  • When Things Go Wrong Westerly Town Property After Tropical Storm Sandy Building was Demolished After Storm
  • House in Charlestown Damage caused by hurricane Sandy
  • House in Anegada, BVI One of several cottages damaged due to severe shoreline erosion
  • Jamestown, Rhode Island Shoreline Protection Is Currently Under Re-Construction
  • Erosion @ Coast Guard House, Narragansett, RI
  • Forces Under Piers/Bridge Decks
  • Bridge Across Escambia Bay, Florida Hurricane Ivan 9/16/2004
  • Biloxi Bay Bridge, Mississippi Hurricane Katrina
  • U.S. 90 Biloxi Bay Bridge Hurricane Katrina
  • SUMMARY • Design is complex & requires several design parameters – – – – – – – – – – Wave height for design Storm flood depth (SWL) Water depth (bathymetry) Affect on littoral transport End effects Structure use Can structure sustain damage Permit ability Constructability Cost