English Version of the Book of Design of Marine and Offshore Structures

1. English Version
Design of
Marine and Offshore
Structures
By:
Prof. Kabir Sadeghi
Khajeh Nasireddin Toosi University of Technology Publishing House

2. Table of contents
Title
Chapter One: Review of different types of Platforms
1-1- History
1-1-1- Wooden platforms
1-1-2- Steel platforms
1-2- Types of platforms
1-2-1- Fixed platforms
1-2-1-1- Template fixed platforms
1-2-1-2- Tower platforms
1-2-1-3- Guyed tower platforms
1-2-1-4- Gravity platforms
1-2-1-5- Tension leg platforms
1-2-2- Floating and mobile platforms
1-2-2-1- Self-lifting drilling platforms (Jack-up)
1-2-2-2- Submersible platforms
1-2-2-3- Semi-submersible platforms
1-2-2-4- Ship-type platforms
1-3- Recommendations of suitable platform type for installation in the Persian
Gulf
Chapter 2: Review of principles of design and calculation of fixed offshore
platforms (Template types)
a- Overall
b- Design codes
c- Available computer programs
d- Operational data in design
e- Environmental data in design
f- Soil conditions and location of platform installation
g- Definitions of forces and loads applied to the platform
h- Calculation of loads
2-1- Wave theories
Short amplitude wave theory (Airy wave)
Stokes waves
Theory of stream function
Cnoidal waves and the solitary waves
Trochoidal wave
2-2- Review of waves generation and effective factors in the design
2-2-1- Sea state
2-2-2- Generation and prediction of waves caused by wind
2-2-3- Effects of the seabed on the wave characteristics in shallow water
2-3- Review of forces applied to the piles and the platform legs due to waves
Page
1
1
1
2
5
5
5
7
10
15
21
22
22
24
29
31
31
36
36
36
37
38
40
42
43
44
46
51
56
57
57
63
65
65
71
83
106

3. Title
2-3-1- Cylindrical vertical piles and ordinary waves
2-3-1-1- Selection of drag and inertia hydrodynamic coefficients
2-3-1-2- Calculation of forces and moments caused by waves
2-3-1-3- Calculation of lateral forces due to Eddy effects (uplifting force)
2-3-2- Calculation of forces applied to non-vertical cylindrical piles
2-3-3- Calculation of forces and moments applied to the cylindrical pile due to
breaking waves
2-3-4- Calculation of forces applied to the piles with non-circular sections
2-4- Calculation of forces and moments caused by the waves on group piles
(platforms of jetty legs)
2-5- Review of forces caused by the impact of the ship on platforms and jetties
2-5-1- Boat landing in jetties and platforms
2-5-2- Loading due to ships impact
2-5-3- Types of fenders
2-5-4- General specifications of boat landings in ports
2-5-5- Loads that should be considered in the boat landing design of jetties
2-6- Review of forces applied to platforms due to wind
2-7- Review of forces due to ship mooring
2-8- Seawater current
2-9- Earthquake
2-10- Effects of tides in the design of platforms
2-11- Review of marine fouling problems and their effects on calculations
2-12- Piles of template fixed platform
2-12-1- Overall
2-12-2- Single vertical piles subjected to lateral loads
2-12-3- Calculation of ultimate strength for lateral loads
Ultimate strength of short rigid piles
2-12-4- Ultimate strength of long piles
2-12-5- Bending and buckling of single vertical piles that partially are driven
to the ground
2-12-6- Deformation of vertical piles under lateral loading
2-12-7- Elastic analysis of piles under load loading
2-12-8- Using P-Y curves
2-12-9- The effect of the method of pile driving on the behaviour of the pile
under the lateral load and moment applied to the head of the pile
Page
108
112
121
152
155
158
160
161
171
171
172
190
190
193
202
204
204
204
205
205
208
208
212
217
220
227
233
235
240
254
265

4. Title
2-12-10- Lateral loads on inclined piles
2-12-11- Lateral loading on the pile group
Numerical examples
2-12-12- Code items about the foundation of fixed offshore platforms
2-12-13- Computer programs to calculate piles
2-13- Protection of platform against corrosion of environment and seawater
2-14- Soil-structure interaction in pile foundations
2-15- Review of code items about design, construction and installation of
platforms
2-15-1- Installation forces
2-15-2 Design of steel structure of the platform
2-15-2-1- Main stresses
2-15-2-2- Structural function of steel cylindrical members
2-15-2-3- Fatigue
2-15-2-4- Hydrostatic collapse
2-16- Review of the deck and location of the helicopter landing (helideck) and
their computational items
Chapter 3: Manual calculation of a sample platform
Chapter 4: Natural conditions of the Persian Gulf
4-1- General geographical conditions of the Persian Gulf
4-2- Geographical and geological status
4-3- Meteorology
4-4- Hydraulic status of the Persian Gulf
4-5- Seismology
4-6- Seawater corrosion in the Persian Gulf
Appendices
References and bibliography
Page
266
267
272
287
297
297
301
307
308
311
311
312
316
317
320
325
377
377
378
380
388
403
403
405
453

5. Page 4:
Chapter 1
Review of the types of platforms
1-1- History
1-1- 1- Wooden Platforms (Preliminary Platforms)
Probably the first attempt to obtain offshore oil was made in California around 1900 AD
when oil wells were drilled from a jetty attached to the shore, with a distance of 500 meters
from the shoreline.
In 1909 or 1910 (AD), a wooden platform was built on the Ferry1
Lake in Caddo Parish
La2
using wooden piles and wooden drilling rigs, and wells were drilled from it. Thus, the
connection of the platform to the shore was eliminated and the platform was built using piles
in the sea.
In 1920 (AD) a wooden platform was built in the shallow waters of Maracaibo Lake and
the drilling operations were carried out from it. However, since the intensity of the waves in
this lake is much lower than the sea, it can not be called an offshore platform.
In 1930 (AD), in southern Louisiana, the drilling was carried out from a wooden platform
which a canal was built for the use of barges and boats for transportation.
Construction of wooden platforms using the wooden piles continued somehow in 1933 a
platform was built at a water depth of 3.7 meters and a distance of one kilometer from the
shoreline.
In 1938 (AD) on the shores of McFaddin4
of Texas a wooden platform with
1. Ferry 2. Caddo Parish La 3. Maracaibo 4. McFaddin

6. Page 5:
the dimensions of (15.2 m x 27.4 m) and at a cost of $ 37,900 were built. This platform was
equipped with a boat landing that with a boat was served from another platform connected to
the shore by a space frame2
system. On this space frame, a railway and a truck track were
installed. It was less than a few months after the construction of this platform that the platform
was severely damaged by a storm and the system of piles were destroyed and new piles were
installed to replace the damaged piles.
In 1937(AD), the American company of "Brown & Root" built a wooden platform at a
distance of 6.1 km from the shore at a water depth of 3.4 m.
The construction of wooden platforms continued until 1940 (AD), and after that due to
starting of the Second World War, the extension of operations was suspended.
1-1-2 Steel platforms
During World War II and after it due to the needs of the war, the steel industry developed
significantly and after the end of the war, the construction of steel structures, including steel
platforms, developed. The first steel platform was built in 1946 at a distance of 3.4 km from
the shore and at a depth of 3.4 m. It is worth mentioning that 338 piles were used for the
construction of this platform.
The first steel template platform using the current method (i.e., construction at onshore,
and after transportation, installation at the offshore site) was built in 1947 (AD) in the waters
of the Gulf of Mexico, where the platform was installed at a distance of 29 km from the coast
and at a water depth of 6.1 meters. Then another platform of type was built at a depth of 15.2
meters and thus a new industry was born. During the development of the construction of
platforms, in parallel with the development of the steel industry, the diameter of the piles
increased and their number decreased, and execution methods improved.
1. Boat Landing 2. Trestle 3. Brown & Root 4. Template Platform

7. Page 6:
In the year 1949 (AD), ten platforms were built in the Gulf of Mexico, but with the onset
of the storm due to the forces of the waves, these platforms were either completely destroyed
or damaged severely.
In the mid-1950s, with the development of the steel industry, the piles with a diameter of
76 cm were used, and in 1969 (AD), the piles with a diameter of 122 cm were used.
In 1955 (AD) for the first time with the construction of a platform completely at onshore
and carried by a barge and installed by massive crane barges and installed at a waterdepth of
30.5 meters, the construction of taller platforms became popular and the dimensions of the
platforms were increasing day by day, and the platforms were installed at the deeper waters
and farther from the shore. Figure 1-1 shows the development of the platforms up to 1972
(AD).
In 1976, the Shell Oil Company1
announced that it would install the world's tallest oil
platform (rig) in the waters of the Gulf of Mexico. This platform was complete and equipped
with all the equipment (drilling rig, drilling mud tanks, accommodation for personnel,
production equipment, etc.). The platform was named Cognac and was installed at a distance
of 160 km from southeast of Louisiana and about 15 km from the mouth of the Mississippi at
a waterdepth of 310.9 m, of which about 22.9 m (in addition to the depth of water) was out of
the water. This platform has 24 piles with an outer diameter of 122 cm and a maximum pile
wall thickness of 6.35 cm. The total weight of the platform is 53,5000 metric tons and is
designed for a wave height of 22.9 meters, a wave period of 12 seconds, wind speed of 150
mph and for a linear earthquake is designed for 0.2g and in the plastic mode for 0.4g. The
computer model of this platform includes 700 nodes and 2000 members. Shell and 14 other
companies participated in the work, which cost over $ 250 million.
At present, the tallest fixed template platform2
is installed at a water depth of 315.5
meters in Mexico, and huge concrete fixed gravity platforms3
are in the North Sea.
1. Shell Co. 2. Template Fixed Platform 3. Gravity Platform