1. A TECHNICAL SEMINAR (16SEC107S)
ON
“OFFSHORE PLATFORM”
Submitted by
MOHD OMER AHMED
USN:20298
Under the Guidance of
Miss. Shobha.L
Asst.professor
Civil Engineering Department
VISVESVARAYA TECHNOLOGICAL UNIVERSITY
Jnanasangama, Belgaum- 590018
DEPARTMENT OF CIVIL ENGINEERING
Submitted in Partial fulfillment for the requirements of I Sem M.Tech – Structural Engineering
Internal guide
Dr. Bharathi Ganesh
Prof.and Head
Civil Engineering Department
External guide
Correct Name
Present Designation
Company Name
3. OVERVIEW
INTRODUCTION
• Offshore platforms are used for
exploration of Oil and Gas from under
Seabed and processing.
• The First Offshore platform was
installed in 1947 off the coast of
Louisiana in 6M depth of water.
• Today there are over 7,000 Offshore
platforms around the world in water
depths up to 1,850M
3CSD PRESENTATION
4. OVERVIEW cont.…
• Platform size depends on facilities
to be installed on top side eg. Oil
rig, living quarters, Helipad etc.
• Classification of water depths:
– < 350 M- Shallow water
– < 1500 M - Deep water
– > 1500 M- Ultra deep water
– US Mineral Management
Service (MMS) classifies water
depths greater than 1,300 ft as
deepwater, and greater than
5,000 ft as ultra-deepwater.
4CSD PRESENTATION
5. 5CSD PRESENTATION
OVERVIEW
Offshore platforms can broadly categorized in two types
Fixed structures that extend to the Seabed.
Steel Jacket
Concrete gravity Structure
Compliant Tower
6. Literature review
DECISION ANALYSIS APPROACH TO OFFDHORE PLATFORM DESIGN (Robert G.Bea, S.T Hong, James
D . Mitchell, members, ASCE)
This paper describes and illustrates a methodology with which alternative design strategies for offshore platforms in
combined loading environment may be assessed. The, methodology is structured around a decision analysis approach to
evaluating and selecting among alternatives. Experience with application of this approach to engineering structures for
new offshore frontiers, such as the artic and dewater, indicates that it represents powerful toll to assist development of
optimum engineering decisions.
WAVE FORCE ON DECKS OF OFFSHORE PLATFORMS (R.G Bea, Fellow , ASCE, T.Xu, J.Stear, And
R.Ramos)
The wave crest height according to RP 2A of America petroleum institute (API) is higher than the lower deck elevation
of many existing platforms. The API guideline to determine wave force acting on the deck of these platforms indicate
that most platform cannot survive such loadings. The deck either to raise to clear specified wave crest. A variety of
laboratory test have been performed to address this problem. Several approach have been developed to compute the
wave crest loadings and responses of the platforms to design. They did a study on the performance of platforms in the
Gulf of Mexico that have survived and failed during hurricane wave loading on their decks.
7. EXPERIMENTAL TESTING OF GROUTED CONNECTIONS FOR OFFSHORE SUB STRUCTURES: A CRITICAL
VIEW (Paul Dallyn, Ashraf El-Hamalawali, Alessandro Palmeri, Robert Knight)
Grouted connections have been extensively used in the oil and gas industry for decades, and more recently their applications have
been extended to the offshore wind industry. Unfortunately plain-pipe grouted connections for large-diameter mono pile
foundation have recently exhibit clears sign of insufficient axial capacity. Resulting in slippage between the transition piece and
mono pile. Motivated by the emergency of such problems. This paper presents a critical review of technical literature related to
the experimental testing for grouted connections for offshore substructures , covering all the key materials and design parameters
that influence their capacity, including the confinement provided by pile and sleeve, surface finish, simultaneous bending action,
connection length dynamic loading, early-age cycling during grout curing, grout shrinkage, radial pre-stress and temperature.
OFFSHORE CONCRETE STRUCTURE (Rodrigo Perez Fernandez, Miguel Lams Pardo)
In offshore industry there are two possible materials for the construction of hull of any structure: steel and concrete. Steel is being
widely used in the ship building industry for merchant ships. warships etc. materials such as aluminium glass reinforced plastics
(GRP) or timber are also used in the small units with lengths lower than 100 m and with less adverse condition than in offshore.
Nevertheless, some ships, barges have been built of concrete in the past, but these have been rather isolated case and have not
changed the industry practice.one of the main differences in these priorities is the importance of maintenance and resistance to
fatigue, precisely the areas where concrete perform better.
8. Ships can easily be dry docked for maintenance and repair, while in offshore platform these works have to be done in situ.
So maintenance and fatigue are crucial to them/ beside the aspect, concrete has other advantages, according to a number
of findings several studies .this supports the fact that in recent years concrete offshore units have been built proving that
certain cases the benefits of steel are inferior to those of concrete.
CHLORIDE PENETRATION INTO CONCRETE IN AN OFFSHORE PLATFORM-ANALYSIS OF EXPOSURE
CONDITION (Ronaldo Alves De Medeiros-Junior, Maryangela Geimba De Lima,Priscila Catarine De Brito, Marcelo
Henrique)
In this paper they carried out the research on chloride penetration in three different exposure zones (atmospheric, splash and
tidal) of an offshore concrete platform in the year 2000 and 2005 was analysed. the apparent diffusion coefficient and surface
chloride content of the concrete specimen were determined by curve fitting of chloride profile in chloride penetration models
based in diffusion. They find that the main factors responsible for increase in chloride content were exposure to wind wetting
and dry cycles.
In conclusion they said that, different types of intensity degradation exist in the same concrete structure exposed in a marine
environment.
RECENT STUDIES ON DURABILITY OF CONCRETE STRUCTURE (S.W. Tang ,Y.Yao , C.Andrade, Zj.Li)
Durability of concrete has attracted significance attentions over the past several decades and is still a research hotspot until now
.this paper reviews and discuss the recent research activities on the durability of concrete, including
9. 1. Major durability problem such as alkali aggregate reactions, sulphate attack, steel corrosion and freeze-thaw.
2. Durability of concrete in marine environment and
3.Coupling effect of mechanical load and environment factors on durability of concrete.
In conclusion they mention that, in general consensus is adding optimal type and amount of pozzolonic
materials is a cost- effective approach to improve the durability performance to some extent.
11. TYPE OF PLATFORMS (FIXED)
• JACKETED PLATFORM
– Space framed structure with tubular
members supported on piled foundations.
– Used for moderate water depths up to 400
M.
– Jackets provides protective layer around
the pipes.
– Typical offshore structure will have a
deck structure containing a Main Deck, a
Cellar Deck, and a Helideck.
– The deck structure is supported by deck
legs connected to the top of the piles. The
piles extend from above the Mean Low
Water through the seabed and into the
soil.
11CSD PRESENTATION
12. TYPE OF PLATFORMS (FIXED)
• JACKETED PLATFORM (Cont.)
– Underwater, the piles are contained
inside the legs of a “jacket” structure
which serves as bracing for the piles
against lateral loads.
– The jacket also serves as a template for
the initial driving of the piles. (The
piles are driven through the inside of
the legs of the jacket structure).
– 95% of offshore platforms around the
world are Jacket supported.
12CSD PRESENTATION
13. TYPE OF PLATFORMS (FIXED)
• COMPLIANT TOWER
– Narrow, flexible framed
structures supported by piled
foundations.
– Has no oil storage capacity.
Production is through tensioned
rigid risers and export by
flexible or catenary steel pipe.
– Undergo large lateral deflections
(up to 10 ft) under wave
loading. Used for moderate
water depths up to 600 M.
13CSD PRESENTATION
14. TYPE OF PLATFORMS (FIXED)
• CONCRETE GRAVITY STRUCTURES:
– Fixed-bottom structures made from concrete
– Heavy and remain in place on the seabed without the
need for piles
– Used for moderate water depths up to 300 M.
– Part construction is made in a dry dock adjacent to the
sea. The structure is built from bottom up, like onshore
structure.
– At a certain point , dock is flooded and the partially built
structure floats. It is towed to deeper sheltered water
where remaining construction is completed.
– After towing to field, base is filled with water to sink it
on the seabed.
– Advantage- Less maintenance
14CSD PRESENTATION
15. TYPE OF PLATFORMS (FLOATER)
• Tension Leg Platform (TLP)
– Tension Leg Platforms (TLPs) are floating
facilities that are tied down to the seabed
by vertical steel tubes called tethers.
– This characteristic makes the structure
very rigid in the vertical direction and
very flexible in the horizontal plane. The
vertical rigidity helps to tie in wells for
production, while, the horizontal
compliance makes the platform insensitive
to the primary effect of waves.
– Have large columns and Pontoons and a
fairly deep draught.
15CSD PRESENTATION
16. TYPE OF PLATFORMS (FLOATER)
• Tension Leg Platform (TLP)
– TLP has excess buoyancy which
keeps tethers in tension. Topside
facilities , no. of risers etc. have
to fixed at pre-design stage.
– Used for deep water up to 1200
M
– It is sensitive to topside
load/draught variations as tether
tensions are affected.
16CSD PRESENTATION
17. TYPE OF PLATFORMS (FLOATER)
• SEMISUB PLATFORM
– Due to small water plane area , they
are weight sensitive. Flood warning
systems are required to be in-place.
– Topside facilities , no. of risers etc.
have to fixed at pre-design stage.
– Used for Ultra deep water.
– Semi-submersibles are held in place
by anchors connected to a catenary
mooring system.
17CSD PRESENTATION
18. TYPE OF PLATFORMS (FLOATER)
• SPAR:
– Concept of a large diameter single vertical
cylinder supporting deck.
– These are a very new and emerging concept:
the first spar platform, Neptune, was installed
off the USA coast in 1997.
– Used for Ultra deep water depth of 2300 M.
– The center of. buoyancy is considerably
above center of gravity , making Spar quite
stable.
– Due to space restrictions in the core, number
of risers has to be predetermined
18CSD PRESENTATION
19. TYPE OF PLATFORMS (FLOATER)
• SHIP SHAPED VESSEL (FPSO)
– Ship-shape platforms are called Floating Production,
Storage and Offloading (FPSO) facilities.
– FPSOs have integral oil storage capability inside
their hull. This avoids a long and expensive pipeline
to shore.
– Can explore in remote and deep water and also in
marginal wells, where building fixed platform and
piping is technically and economically not feasible
– FPSOs are held in position over the reservoir at a
Single Point Mooring (SPM). The vessel is able to
weathervane around the mooring point so that it
always faces into the prevailing weather.
19CSD PRESENTATION
20. PLATFORM PARTS
• TOPSIDE:
– Facilities are tailored to achieve
weight and space saving
– Incorporates process and utility
equipment
• Drilling Rig
• Injection Compressors
• Gas Compressors
• Gas Turbine Generators
• Piping
• Instrumentation
– Accommodation for operating
personnel.
– Crane for equipment handling
– Helipad
20CSD PRESENTATION
21. PLATFORM PARTS
• MOORINGS & ANCHORS:
– Used to tie platform in place
– Material
• Steel chain
• Steel wire rope
– Catenary shape due to heavy
weight.
– Length of rope is more
• Synthetic fiber rope
– Taut shape due to substantial
less weight than steel ropes.
– Less rope length required
– Corrosion free
21CSD PRESENTATION
22. PLATFORM PARTS
• RISER:
– Pipes used for production,
drilling, and export of Oil and
Gas from Seabed.
– Riser system is a key component
for offshore drilling or floating
production projects.
– The cost and technical challenges
of the riser system increase
significantly with water depth.
– Design of riser system depends
on filed layout, vessel interfaces,
fluid properties and
environmental condition.
22CSD PRESENTATION
23. PLATFORM PARTS
• RISER:
– Remains in tension due to self weight
– Profiles are designed to reduce load on
topside. Types of risers
• Rigid
• Flexible - Allows vessel motion
due to wave loading and
compensates heave motion
– Simple Catenary risers: Flexible
pipe is freely suspended
between surface vessel and the
seabed.
– Other catenary variants possible
23CSD PRESENTATION
24. PLATFORM
INSTALLATION
• BARGE LOADOUT:
– Various methods are deployed
based on availability of resources
and size of structure.
• Barge Crane
• Flat over - Top side is installed
on jackets. Ballasting of barge
• Smaller jackets can be
installed by lifting them off
barge using a floating vessel
with cranes.
24CSD PRESENTATION
25. CORROSION PROTECTION
• The usual form of corrosion protection of the underwater part
of the jacket as well as the upper part of the piles in soil is by
cathodic protection using sacrificial anodes.
• A sacrificial anode consists of a zinc/aluminium bar cast about
a steel tube and welded on to the structures. Typically
approximately 5% of the jacket weight is applied as anodes.
• The steelwork in the splash zone is usually protected by a
sacrificial wall thickness of 12 mm to the members.
25CSD PRESENTATION
26. STRUCTURAL DESIGN
• Loads:
• Offshore structure shall be designed for following types
of loads:
– Permanent (dead) loads.
– Operating (live) loads.
– Environmental loads
– Wind load
» Wave load
» Earthquake load
– Construction - installation loads.
– Accidental loads.
• The design of offshore structures is dominated by
environmental loads, especially wave load
26CSD PRESENTATION
27. STRUCTURAL DESIGN
• Permanent Loads:
Weight of the structure in air, including
the weight of ballast.
– Weights of equipment, and associated
structures permanently mounted on the
platform.
– Hydrostatic forces on the members
below the waterline. These forces
include buoyancy and hydrostatic
pressures.
27CSD PRESENTATION
28. STRUCTURAL DESIGN
• Operating (Live) Loads:
– Operating loads include the weight of all non-
permanent equipment or material, as well as forces
generated during operation of equipment.
• The weight of drilling, production facilities, living
quarters, furniture, life support systems, heliport,
consumable supplies, liquids, etc.
• Forces generated during operations, e.g. drilling,
vessel mooring, helicopter landing, crane
operations.
• Following Live load values are recommended in
BS6235:
Crew quarters and passage ways: 3.2 KN/m2
Working areas: 8,5 KN/m2 28CSD PRESENTATION
29. STRUCTURAL DESIGN
• Wind Loads:
• Wind load act on portion of platform above the water level as
well as on any equipment, housing, derrick, etc.
• For combination with wave loads, codes recommend the most
unfavorable of the following two loadings:
–1 minute sustained wind speeds combined with extreme
waves.
29CSD PRESENTATION
30. STRUCTURAL DESIGN
30CSD PRESENTATION
Wave load:
The wave loading of an offshore structure is usually the most
important of all environmental loadings.
The forces on the structure are caused by the motion of the water due
to the waves
Determination of wave forces requires the solution of ,
a) Sea state using an idealization of the wave surface profile and the
wave kinematics by wave theory.
b) Computation of the wave forces on individual members and on the
total structure, from the fluid motion.
31. STRUCTURAL DESIGN
31CSD PRESENTATION
Ice and Snow Loads:
Ice is a primary problem for marine structures in the arctic and sub-arctic
zones. Ice formation and expansion can generate large pressures that give rise
to horizontal as well as vertical forces. In addition, large blocks of ice driven
by current, winds and waves with speeds up to 0,5 to 1,0 m/s, may hit the
structure and produce impact loads.
Temperature Load:
Temperature gradients produce thermal stresses. To cater such stresses,
extreme values of sea and air temperatures which are likely to occur during
the life of the structure shall be estimated. In addition to the environmental
sources , accidental release of cryogenic material can result in temperature
increase, which must be taken into account as accidental loads. The
temperature of the oil and gas produced must also be considered.
32. STRUCTURAL DESIGN
32CSD PRESENTATION
Installation Load :
These are temporary loads and
arise during fabrication and
installation of the platform or its
components. During fabrication,
erection lifts of various
structural components generate
lifting forces, while in the
installation phase forces are
generated during platform load
out, transportation to the site,
launching and upending, as well
as during lifts related to
installation.
33. STRUCTURAL DESIGN
33CSD PRESENTATION
Accidental Load :
Accidental loads are loads, which may occur as a result of
accident or exceptional circumstances.
Examples of accidental loads are, collision with vessels, fire or
explosion, dropped objects, and unintended flooding of buoyancy
tanks.
Special measures are normally taken to reduce the risk from
accidental loads.
34. STRUCTURAL DESIGN
34CSD PRESENTATION
Load Combinations :
The load combinations depend upon the design method used, i.e. whether limit state
or allowable stress design is employed.
The load combinations recommended for use with allowable stress procedures are:
Normal operations
Dead loads plus operating environmental loads plus maximum live loads.
Dead loads plus operating environmental loads plus minimum live loads.
Extreme operations
Dead loads plus extreme environmental loads plus maximum live loads.
Dead loads plus extreme environmental loads plus minimum live loads
Environmental loads,should be combined in a manner consistent with their joint
probability of occurrence.
Earthquake loads, are to be imposed as a separate environmental load, i.e., not to be
combined with waves, wind, etc.
35. STRUCTURAL ANALYSIS
• ANALYSIS MODEL:
• The analytical models used in offshore engineering are similar to other
types of on shore steel structures
• The same model is used throughout the analysis except supports
locations.
• Stick models are used extensively for tubular structures (jackets,
bridges, flare booms) and lattice trusses (modules, decks).
• Each member is normally rigidly fixed at its ends to other elements in
the model.
• In addition to its geometrical and material properties, each member is
characterized by hydrodynamic coefficients, e.g. relating to drag,
inertia, and marine growth, to allow wave forces to be automatically
generated.
35CSD PRESENTATION
36. • Acceptance Criteria:
• The verification of an element consists of comparing its characteristic
resistance(s) to a design force or stress. It includes:
• a strength check, where the characteristic resistance is related to the
yield strength of the element,
• a stability check for elements in compression related to the buckling
limit of the element.
• An element is checked at typical sections (at least both ends and mid
span) against resistance and buckling.
• Tubular joints are checked against punching. These checks may
indicate the need for local reinforcement of the chord using larger
thickness or internal ring-stiffeners.
• Elements should also be verified against fatigue, corrosion,
temperature or durability wherever relevant.
36CSD PRESENTATION
37. CASE STUDY
ON
OFFSHORE CONCRETE STRUCTURES
BRIEF HISTORY OF THE SHIPS AND
STRUCTURES OFFSHORE THAT USE
CONCRETE
• The use of concrete in marine structures
dates back to ancient Rome and Greece, and
its use extends to diverse applications such
as bridges, piers, dock sand lighthouses. But
the use of concrete as a building material for
commercial hull vessels began in the late
nineteenth century
• The first concrete platform for oil and gas
production in the Gulf of Mexico was
installed in 1950 and since then there have
been more than1000 small concrete-like
structures built in that area
38. Cont.….
• But the first major concrete
offshore structure supported
at its base by gravity, gravity
base structure (GBS), was
installed in1973 in the North
Sea: the Ekofisk tank
• The LNG terminal Adriatic,
the concrete box built by
Acciona in Algecirasin2007,
is the last major mile stone in
concrete offshore structures
in spain
39. CHARACTERISTICS OF CONCRETE IN PREFERENCE
TO STEEL
Of all types of concrete, two are applied in shipbuilding and offshore industry:
reinforced concrete and pre-stressed concrete. We compared the steel properties
against more typical shipbuilding material.
1. REINFORCED CONCRETE
2. PRE-STRESSED CONCRETE
1. REINFORCED CONCRETE
Reinforced concrete is found inside steel armour, properly calculated and placed.
This concrete is able to with stand compressive forces and traction
40. Cont..
• The tensile stress of steel reinforcement is resisted by
reinforced steel.
• Reinforced concrete has far fewer maintenance requirements
than steel.
• How- ever, if loaded with tension, the concrete develops
cracks overtime, which may cause the bar to rust.
• Even so, the cost per weight of concrete is much cheaper
than steel, so the concrete structure would have a lower cost.
41. 2. PRE-STRESSED CONCRETE
• Pre-stressed concrete has
special steel reinforcement
under tension inside, which
yields much higher tensile
stress than normal concrete.
• In pre-stressed concrete steel
tensioning supports all loads,
and the concrete role simply
completes protection against
corrosion and as a non-
thermal link (non-thermal
bond) for steel.
42. ADVANTAGES CONCRETE OFFSHORE
STRUCTURES
Concrete offshore structures show excellent performance:
They have very high durability.
They are constructed of maintenance-free materials. Better
performance in motion, in the case of floating structures.
They are suitable for harsh and /or arctic environments, such as
ice and seismic regions.
Can carry heavy topsides (equipment and oil systems on deck).
Provide storage capacity within the structure.
43. Most supported platform sat the bottom, gravity based, do not
need an additional anchor because of the large dimensions and
weight of its support, which makes them suitable for soft and
shaky floors.
Fire resistant.
Free of sparks, making them ideal as storage for flammable and
explosive charges and, therefore, function as a bunkering barge,
FPSOs, LNG terminal sand in general for the offshore oil and
gas industry.
Pollution due to corrosion and other damage to the load is
minimized by the low thermal conductivity and corrosion
resistance of concrete
44. Types of concrete structures in the industry offshore
Supported Structures in the
deep—Gravity base structures
(GBS)
• Concrete structures supported on the
bottom, concrete gravity base
Structures (CGBS) or simply
concrete gravity substructure (CGS),
run their support loads directly over
the upper layers of the seabed that
supports them.
• The structure provides buoyancy
during construction and towing and
acts at the same time as structural
support in the operation phase.
Furthermore, the structure can be
used as storage for oil and other
liquids
45.
46. Cylindrical tanks type
• The first concrete offshore platform in
the North Sea was the Ekofisk, which
was built in 1973 as the concept of the
French– Canadian compagnie general
des pour les Richesse operationelles
developments Sous Sous-
Marines(CGDORIS)to Phillips
petroleum.
• The design consists of a large box made
up of cylindrical tanks that once
attached from a single structure that
forms the basis for the upper deck. It is
supported at the bottom of the sea and
surrounded in turn by an exterior
breakwater, built in two pieces
47. Condeep type
• Between 1975 and1995 a total of
fourteen condeeps settled in the
North Sea (Holand etal.,2003) with
depths of 104 m to 30 m, the Aker
Kvaerner shipyard in Hinna (near
Stavanger, Norway)was in charge
of building them.
• The most recent project
developments Condeep with
rectangular cells is by Arup for
ExxonMobil Sakhalin II Project
(Russia) The following figure
shows the layout of the two CGS
vessels designed by Arup The base
was90m-100 with a depth of 12 m
48. CIDS (concrete island drilling system)
• The Concrete Island Drilling
Platform System (CIDS) was
built in 1984 with precast pre-
stressed concrete to withstand
the severe pressure of ice in the
Arctic.
• This platform replaces the
construction of islands made of
gravel which cost at the time
about $100 million.
• In contrast, CIDS cost only $75
million and was reused to
explore numerous locations
along the north coast of Alaska
and Russia without having
shown any deterioration.
49. Adriatic LNG terminal
This is the first offshore
gas terminal that has
been installed in the
world The terminal
consists of a pre-stressed
concrete structure resting
on the bottom GBS 180
m long, 88 m wide and
47 m in height, whose
budget was over 200
million euros
50. Floating structures
1) Semi-submergible and TLP type
2) Barge type
• Since concrete is very resistant to salt water and keeps maintenance costs low,
floating concrete structures have become quite attractive for oil and gas
industry in recent decades.
• Temporarily floating platforms such as Condeep float during construction and
towing, but are finally placed on the ocean floor Permanently floating concrete
structures were used in the discovery of oil and gas deposits for production. Sto
• rage, offloading units and in some cases as a system of heavy lifting.
1) Semi-submergible and TLP type
• The geometry of semisubmersible and TLP platforms are very similar.they
have a pontoon at the bottom and stabilization columns that cross the waterline
to support the steel deck.
• The differences are mainly the anchoring system: while the semisubmersible
type has a traditional system of anchors, anchor chains in catenarythe TLP has
an anchoring system with steel tendons fixed vertically at the bottom, which do
not allow the vertical movements
51.
52. 2) Barge type
The FPSO and FSO are
units for oil and gas storage
tanks located in the ship’s
hull which remain anchored
to the bottom through a
turret or other mooring
system that allows the ship
to find the best wind
conditions and waves,
allowing the flow of oil/
gas
53. New concepts
• As we have seen in previous
sections, the use of floating concrete
structures has reduced to a few cases.
• However, in the last few years an
increase in interest has been observed
being the offshore industry that
desires this, pushed by the necessity
has fed more to develop to fields of
petroleum and gas in more and more
hard regions, like the Arctic, where
concrete has a better behaviour than
steel.
• In addition it has been caused by the
necessity to develop more terminals
of import and export for LNG, since
the behaviour of concrete is superior
to steel as hull for cryogenic storage
of liquids since we have seen
previously
54. Cont.…
• In addition to these demands,
the use of concrete in
offshore structures is also
being applied in conceptual
ideas of very large floating
structures (VLFS) like
floating airports, as well as in
floating wind generators,
although they are being
designed in steel they have a
better alternative in concrete
55. 55CSD PRESENTATION
REFERENCES
• Ronaldo Alvesde Medeiros-Junior Maryangela Geimbade Lima Priscila Catarinede Brito ,
Marcelo Henrique Fariasde Medeiros
• S.W. Tang, Y. Yao C. Andrade Z.J. Li
• Rodrigo Pe´ rez Ferna´ndez Miguel Lamas Pardo
• Paul Dallyn, Ashraf El-Hamalawi, Alessandro Palmeri, Robert Knight.
• Ronaldo Alves De Medeiros-Junior, Maryangela Geimba De Lima,Priscila Catarine De Brito,
Marcelo Henrique
• R.G Bea, Fellow , ASCE, T.Xu, J.Stear, And R.Ramos .
• W.J. Graff: Introduction to offshore structures.
– Gulf Publishing Company, Houston 1981.
– Good general introduction to offshore structures.
– Civil engg,today,Technical Journal of ASCE-IS
– WWW.wikipedia.com
– WWW.sptoffshore.com
