DESIGN OF A MODEL HAULAGE TECHNIQUE FOR WATER FLOODING CAISSON ASSEMBLY.

CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF STUDY
Offshore construction is the installation of structures and facilities in a marine environment,
usually for the production and transmission of electricity, oil, gas and other resources.
Construction and pre-commissioning is typically performed as much as possible onshore. To
optimize the costs and risks of installing large offshore structures, different construction
strategies have been developed. (API, 1984)
One strategy is to fully construct the offshore facility onshore, and tow the installation to site
floating on its own buoyancy. Bottom founded structure are lowered to the seabed by de-
ballasting (see for instance Condeep or Cranefree), whilst floating structures are held in position
with substantial mooring systems.The size of offshore lifts can be reduced by making the
construction modular, with each module being constructed onshore and then lifted using a crane
vessel into place onto the platform( Chakrabarti, S. K. (ed), 2005). A number of very large crane
vessels were built in the 1970s which allow very large single modules weighing up to 14,000
tonnes to be fabricated and then lifted into place. (API, 1984).Specialist floating hotel vessels
known as flotels are used to accommodate workers during the construction and hook-up phases.
This is a high cost activity due to the limited space and access to materials.Oil platforms are key
fixed installations from which drilling and production activity is carried out. Drilling rigs are
either floating vessels for deeper water or jack-up designs which are a barge with liftable legs.
Both of these types of vessel are constructed in marine yards but are often involved during the
construction phase to pre-drill some production wells. Other key factors in offshore construction
are the weather window which defines periods of relatively light weather during which
continuous construction or other offshore activity can take place. Safety is another key
construction parameter, the main hazard obviously being a fall into the sea from which speedy
recovery in cold waters is essential.( DNV-OS-C101, 2004).The main types of vessels used for
pipe laying are the "Derrick Barge (DB)", the "Pipelay Barge (LB)" and the "Derrick/Lay barge
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(DLB)" combination. Diving bells in offshore construction are mainly used in water depths
greater than 120 feet (40 m), less than that, the divers use a metal basket driven from an "A"
frame from the deck. The basket is lowered to the water level, then the divers enter the water
from it to a maximum of 120 feet (40 m). Bells can go to 1,500 feet (460 m), but are normally
used at 400 to 800 feet (120 to 240 m).
1.2 AIM AND OBJECTIVE(S)
The aim of the study is to adopt basic engineering solutions in lifting, transportation and
installation of a 63m, 45 tons Caisson from a fabrication Agege, Lagos State to Bonga FPSO,
noting all the design criteria’s necessary in achieving the solution. The objective seeks;
1. To identify Caissons used for water flooding and the essence of water flooding for a
typical EA FIELD.
2. To identify the general knowledge of installation of subsea structures offshore.
3. To establish a global caisson model in SACS; apply appropriate Member properties, joint
fixity, loading on the caisson due to sling, sea state configuration.
4. A full description of the installation procedure to be adopted for the installation of the
caisson onto the FPSO will involves;
a. Description of lifting the caisson from the quayside to the vessel with analysis to
support the procedure.
b. Spreader bar, sling, clamp, pad eye and shackle design to be used to validate the
procedure.
c. The vessel to be used in transportation from Dorman long yard, to also check the
six degree of freedom; Surge (longitudinal movement), Sway (perpendicular
movement) , Heave (vertical movement), Roll (rotation about longitudinal axis),
Pitch (rotation about transverse axis), Yaw (rotation about vertical axis) to be
used in the vessel motion while carrying the caisson to the FPSO.
d. Sea fastening of the caisson onto the vessel to keep in static position and to avoid
failure due to hydrodynamic effects on the vessel while in motion.
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e. Caisson will be analysed at angle 30, 60 & 90 degree to achieve possible failures
during lifting operation with the aid of a modelled sling from the vessel onto the
FPSO.
2. The necessary checks will be made to ensure conform to the relevant codes.
1.3 STATEMENT OF PROBLEM
1. There are many issues that affect the productivity of mature fields, but one key source of
downtime is artificial lift repair and maintenance.
2. In order to sustain the water flooding capacity, a third pump is required to be installed.
This will ensure water flooding capacity and provide flexibility for maintenance work on
the pumps.
3. Since the caisson is heavy (45tons) and long (63m), we are faced with difficulty in lifting
it conveniently onto the vessel so this thesis is to prefer solution possible ways of lifting it
from the quayside to the vessel to transport it to the FPSO.
4. A suitable vessel for transportation to the FPSO is necessary due to hydrodynamic forces
offshore, so careful analysis will be done in the selection of the transport vessel.
5. To avoid minimum deflection during lifting operation from the vessel to install it onto the
FPSO, because any little deflection can cause the caisson not to fit into the caisson guide..
1.4 SCOPE OF STUDY
The scope of the study involves developing a model, using the software, SACS to verify the
structural integrity of the caisson to be installed to the FPSO which will involve:
1. To verify the workability of the lifting procedure and technique from the quayside
onshore to the crane barge, the avoid deflection, and to check joints that are likely to fail
during the lifting process onto the vessel.
2. To design the elements to be used in the lifting procedure which includes Shackles,
Slings, Spreader bars.
3. Transportation analysis which involves, Pad eye design, clamp design, sea fastening
design using STAADPRO.
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4. Lifting the caisson from the vessel onto the FPSO, moment checks, deflection checks,
unity checks for 30, 60 static analysis without Dynamic Amplification Factor (DAF) and
90 decrees lifting analysis will be done to check workability in relation to relevant codes
and standards.
1.5 SIGNIFICANCE OF STUDY
1. This study is carried out so as achieve the purpose of duplicating a critical component in
other to increase the reliability of the water flooding system in the FPSO.
2. This study is to achieve at great length the lifting technique to be adopted in lifting a long
tubular member onto a crane barge.
3. This study is to assess the transportation analysis of the Caisson to be installed to the
FPSO.
4. This study is to assess the sea fastening methodology of the Caisson to the deck of a
crane barge to be used to transport the caisson to the FPSO.
5. This study is to assess the criteria in installing the caisson from the crane barge onto the
FPSO.
1.6 LIMITATION OF STUDY
1. This thesis is limited to the initial design and fabrication of the 63m caisson.
2. This thesis is for guidance only.
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CHAPTER TWO
LITERATURE REVIEW
Rigging practices date back centuries in Europe, but modern cable yarding practices were
developed in the late 19th century with the advent of steam powered engines like the Dolbeer
Steam donkey in 1881 in Eureka, California (www.ci.eureka.ca.gov). Modern cable logging with
integrated tower yarders (referred to as haulers in New Zealand) was introduced into plantation
forestry in the 1950’s, with the development of diesel yarders, and have continued to be the
preferred method of extracting timber on slopes limiting conventional ground based equipment
around the world (Kirk and Sullman 2001). Rigging is also preferred due to its’ environmental
benefits over ground based yarding, because the partial or full suspension of logs generated
results in minimal soil disturbance (McMahon 1995; Visser 1998). Alternatives, such as
modified ground-based equipment and helicopters exist for the extraction of timber on steep
slopes. Helicopters are not often preferred due to their high rate of fuel consumption and
expensive operating costs. Modified ground-based equipment are limited in their application due
to their short economic yarding distance and their difficulty in traversing rough terrain.
Despite its wide use and environmental benefits cable logging is expensive, has tended to have
high incidence of accidents to workers, and is generally less productive than ground-based
methods of harvesting timber (Slappendel et al. 1993). Even those who have had only a brief
introduction to cable logging appreciate that it is more complex than either tractor or skidder
logging.
Rigging practices can vary widely world-wide, with significant differences in types of machines
and the selection of rigging and accessories. Two main regions of significant development
include the Pacific North West and central Europe. Rigging as it is practiced offshore differs in
several respects from how it is practiced elsewhere, especially in terms of choice of rigging
configurations.
Evanson and Amishev (2010) have investigated new equipment development options to push the
limits of ground based machinery on steep terrain. However, as ground based machinery become
increasingly dangerous and less productive to operate on steep terrain (> 45% slope);
When using a yarder for cable extraction the main criteria determining the extraction method to
be used is the ground slope or profile, of the area to be harvested (Visser 1998). The first
5

decision made is whether the extraction of timber will be uphill or downhill. Then there are a
variety of factors including desired lift, tower height of the yarder, number of drums for the
yarder, crew size, and availability of carriages and gear, to name a few, which all determine One
of the most common challenges in cable logging operations is deciding when and where to use
which rigging configuration and furthermore, which gear to pair with the chosen configuration.
However, very few provide any detailed information as to which system will be more productive,
or safer, under given stand and terrain conditions. Before improvements to current practices can
be made, one must first gain a better understanding of the abilities and limitations between the
various rigging systems.
The study is done to determine the current use and applications of rigging configurations and
equipment offshore Nigeria,rigging operations emphasis was placed on appropriate rigging
configuration selection, given their perceived advantages and disadvantages, as well as some
operational variables such as yarding distance and deflection.Lift installation of a major marine
or offshore structure necessitates detailed evaluation ofinter-dependent engineering and
construction constraints that influence the feasibility, safetyand cost-effectiveness of the lifting
operations. Due to the advancements in heavy lifttechnology, largemodularized ship blocks may
be fully outfitted, and then lifted and joined to form the entire ship. Similarly, an offshore
structure may be fabricated in a yard, transported to the selected offshore location, and then
installed by lifting. The objectives of this paper are to find the possible lifting configuration for
heavy offshore structures using the method of evolution strategies either minimizing the moment
or maximizing the natural frequency.
2.1 DESCRIPTION OF THE LIFTING MATERIALS TO BE USED FOR THE
INSTALLAMENT
2.1.1 SHACKLE.
A shackle, also known as a gyve, is a U-shaped piece of metal secured with a clevis pin or bolt
across the opening, or a hinged metal loop secured with a quick-release locking pin mechanism.
The term also applies to handcuffs and other similarly conceived restraint devices that function
in a similar manner. Shackles are the primary connecting link in all manner of rigging systems,
from boats and ships to industrial crane rigging, as they allow different rigging subsets to be
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connected or disconnected quickly. A shackle is also the similarly shaped piece of metal used
with a locking mechanism in padlocks. (Edwards, Fred 1988).
• TYPES OF SHACKLE
I. Bow shackle
With a larger "O" shape to the loop, this shackle can take loads from many directions without
developing as much side load. However, the larger shape to the loop does reduce its overall
strength. Also referred to as an anchor shackle. (Edwards, Fred 1988).
II. D-shackle
Also known as a chain shackle, D-shackles are narrow shackles shaped like a loop of chain,
usually with a pin or threaded pin closure. D-shackles are very common and most other shackle
types are a variation of the D-shackle. The small loop can take high loads primarily in line. Side
and racking loads may twist or bend a D-shackle. (Edwards, Fred 1988).
Headboard shackle
This longer version of a D-shackle is used to attach halyards to sails, especially sails fitted with a
headboard such as on Bermuda rigged boats. Headboard shackles are often stamped from flat
strap stainless steel, and feature an additional pin between the top of the loop and the bottom so
the headboard does not chafe the spliced eye of the halyard. (Edwards, Fred 1988).
III. Pin shackle
A pin shackle is closed with an anchor bolt and cotter pin, in a manner similar to a clevis. It is for
this reason they are often referred to, in industrial jargon, as clevises. Pin shackles can be
inconvenient to work with, at times, as the bolt will need to be secured to the shackle body to
avoid its loss, usually with a split pin or seizing wire. A more secure version used in crane
rigging features the combination of a securing nut (hardware) located alongside the cotter pin.
Pin shackles are practical in many rigging applications where the anchor bolt is expected to
experience some rotation. (Edwards, Fred 1988).
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IV. Snap shackle
As the name implies and as shown in plate 2.2, a snap shackle is a fast action fastener which can
be implemented single handedly. It uses a spring activated locking mechanism to close a hinged
shackle, and can be unfastened under load. This is a potential safety hazard, but can also be
extremely useful at times. The snap shackle is not as secure as any other form of shackle, but can
come in handy for temporary uses or in situations which must be moved or replaced often, such
as a sailor's harness tether or to attach spinnaker sheets. Note: When this type of shackle is used
to release a significant load, it will work rather poorly (hard to release) and is likely to have the
pin assembly or the split ring fail. (Edwards, Fred 1988).
V. Threaded shackle
The pin is threaded and one leg of the shackle is tapped as shown in figure 2.1 . The pin may be
captive, which means it is mated to the shackle, usually with a wire. The threads may gall if over
tightened or have been corroding in salty air, so a liberal coating of lanolin or heavy grease is not
out of place on any and all threads. A shackle key or metal marlin spike are useful tools for
loosening a tight nut. (Edwards, Fred 1988).
VI. Twist shackle
A twist shackle is usually somewhat longer than the average, and features a 90° twist so the top
of the loop is perpendicular to the pin. One of the uses for this shackle include attaching the jib
halyard block to the mast, or the jib halyard to the sail, to reduce twist on the luff and allow the
sail to set better. (Edwards, Fred 1988).
2.1.2 PADEYES:
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A padeye is a device often found on boats that a line runs through, or provides an attachment
point as shown in figure 2.2 and plate 2.3. It is a kind of fairlead and often is bolted or welded to
the deck or hull of a boat.( Sarpkaya, T. & Isaacson, M. 1981).
It is also used in oil and gas projects to assist in the purpose of lifting.
• Detail
It's made of steel plate with radius at onside. lifting is done with the help of D-shackle or sling,
which fits into the hole of pad eye. there may be one or more circular plates(cheek plates) welded
around the hole. (Newland, D.E. 1975).
Designing
Following check should be done for the designing of pad eyes and keep the stress less than the
allowable stresses (Le Mehaute, B. 1969)
At the hole:
1. Bearing stress
2. Shear stress
3. Tensile stress
At the base
1. Shear stress
2. Tensile stress
3. Bending stress
4. Combined bending stress and tensile stress
5. Von-Misses stress.
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2.1.3 CAISSON SUPPORT
A pipe support or pipe hanger is a designed element that transfers the load from the Pipe to the
supporting structures. The load includes the weight of pipe proper, the content the pipe carries,
all the pipe fittings attached to pipe & the pipe covering such as insulation. The four main
functions of a pipe support are to anchor, guide, absorb shock and support a specified load. Pipe
supports used in high or low temperature applications may contain insulation materials. The
overall design configuration of a pipe support assembly is dependent on the loading and
operating conditions. (Werner Sölken, 2008-10).
2.1.4 Loads on Piping System
• Primary Load
These are typically steady or sustained types of loads such as internal fluid pressure, external
pressure, gravitational forces acting on the pipe such as weight of pipe and fluid, forces due to
relief or blow down, pressure waves generated due to water/steam hammer effects. (Werner
Sölken, 2008-10).
• Sustained Loads:
.A pipe such as a jacketed pipe core or tubes in a Shell & Tube ex-changer etc. may be under net
external pressure. Internal or external pressure induces stresses in the axial as well as
circumferential (Hoop Stress) directions. The pressure also induces stresses in the radial
direction, but these are often neglected. The internal pressure exerts an axial force equal to
pressure times the internal cross section of the pipe. F =P[πd^2/4]. If outer diameter is used for
calculating approximate metal cross-section as Pressure well as pipe cross-section, the axial
stress can often be approximated as follows : S =Pd /(4t). (Werner Sölken, 2008-10).
• Dead Weight:
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It is the self weight of pipe including fluid, weight of fittings & other inline components (say
valve, insulation etc.). This type of loads acts throughout the life cycle of pipe. These Loads
cause bending and the bending moment is related to normal and shear stresses. Pipe bending is
caused mainly due to two reasons: distributed weight load (e.g. fluid weight) and concentrated
weight load (e.g. valve weight). (Werner Sölken, 2008-10).
• Occasional Loads:
1. Wind Load :
Piping which are located outdoors and thus exposed to wind will be designed to withstand the
maximum wind velocity expected during the plant operating life. Wind force is modeled as a
uniform load acting upon the projected length of the pipe perpendicular to the direction of the
wind. Wind pressure for various elevations will be used to calculate wind force using the
following formula. Fw = Pw x S x A, where Fw = The total wind force, Pw = The equivalent
wind pressure, S = Wind shape factor, A = Pipe exposed area. (Werner Sölken, 2008-10).
2. Seismic Load :
Seismic load is one of the basic concepts of earthquake engineering which means application of
an earthquake-generated agitation to a structure. It happens at contact surfaces of a structure
either with the ground, or with adjacent structures, or with gravity waves from tsunami.
3. Water Hammer :
Water hammer (or more generally, fluid hammer) is a pressure surge or wave caused when a
fluid (usually a liquid but sometimes also a gas) in motion is forced to stop or change direction
suddenly (momentum change). Water hammer commonly occurs when a valve closes suddenly
at an end of a pipeline system, and a pressure wave propagates in the pipe. It's also called
hydraulic shock. (Werner Sölken, 2008-10).
4. Steam hammer:
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Steam hammer, the pressure surge generated by transient flow of super-heated or saturated
steam in a steam-line due to sudden stop valve closures is considered as an occasional load.
Through the flow is transient, for the purpose of piping stress analysis, only the unbalanced force
along the pipe segment tending to induce piping vibration is calculated and applied on the piping
model as static equivalent force. (Werner Sölken, 2008-10).
• Secondary Load
Just as the primary loads have their origin in some force, secondary loads are caused by
displacement of some kind. For example, the pipe connected to a storage tank may be under load
if the tank nozzle to which it is connected moves down due to tank settlement. Similarly, pipe
connected to a vessel is pulled upwards because the vessel nozzle moves up due to vessel
expansion. Also, a pipe may vibrate due to vibrations in the rotating equipment it is attached to.
(Werner Sölken, 2008-10).
• Displacement Loads:
a. Load due to Thermal Expansion of pipe
b. Load due to Thermal movement of Equipment
A pipe may experience expansion or contraction once it is subjected to temperatures higher or
lower respectively as compared to temperature at which it was assembled. The secondary loads
are often cyclic but not always. For example load due to tank settlement is not cyclic. The load
due to vessel nozzle movement during operation is cyclic because the displacement is withdrawn
during shut-down and resurfaces again after fresh start-up. A pipe subjected to a cycle of hot and
cold fluid similarly undergoes cyclic loads and deformation. (Werner Sölken, 2008-10).
• Types of pipe supports
a. Rigid Support
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b. Spring Support
c. Snubber/Shock Absorber
a. Rigid Support
Rigid supports as shown in plate 2.4 are used to restrict pipe in certain direction(s) without any
flexibility (in that direction). Main function of a rigid support can be Anchor, Rest, Guide or both
Rest & Guide. (Werner Sölken, 2008-10).
• Stanchion/Pipe Shoe:
Rigid support can be provided either from bottom or top. In case of bottom supports generally a
stanchion or Pipe Clamp Base is used as shown in plate 2.5 . It can be simply kept on steel
structure for only rest type supports. To simultaneously restrict in another direction separate plate
or Lift up Lug can be used. A pipe anchor is a rigid support that restricts movement in all three
orthogonal directions and all three rotational directions, i.e. restricting al the 6 degrees of
freedom This usually is a welded stanchion that is welded or bolted to steel or concrete In case of
anchor which is bolted to concrete, a special type of bolt is required called Anchor Bolt, which is
used to hold the support with concrete. In this type of support, normal force and friction force
can become significant. To alleviate the frictional effect Graphite Pad or PTFE plates are used
when required. (Werner Sölken, 2008-10).
• Rod Hanger:
It is a static restraint i.e. it is designed to withstand tensile load only (no compression
loadshould be exerted on it, in such case buckling may take place). It is rigid vertical type
support provide from top only. It consists of clamp, eye nut, tie rod, beam attachment.
Selection of rod hanger depends on pipe size, load, temperature, insulation, assembly length
etc. As it comes with hinge and clamp, no substantial frictional force comes into play.
(Werner Sölken, 2008-10).
b. Spring Support
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Spring supports (or Flexible supports) use helical coil compression springs (to accommodate
loads and associated pipe movements due to thermal expansions). They are broadly classified
into Variables Effort support & Constant effort support. The critical component in both the type
of supports is Helical Coil Compression springs. Spring hanger & supports usually use helical
coil compression springs. The springs are manufactured either by the cold coiling process (where
wire diameter is less than 12 mm) or by Hot coiling process Springs are classified as “Light” &
“Heavy” . Light springs are normally cold formed Heavy springs are manufactured by the hot
coiling process. (Werner Sölken, 2008-10).Springs are designed using the formulae :- Spring
Rate ( K ) = (d^4 x G)/8 x (Dm)^3 x Wc Where: d = Wire Dia in mm, Dm= Mean Diameter of
Spring Coil, Wc= Total no of working coils, K = Spring rate or Spring Constant in Kg/mm, G =
Modulus of Rigidity normally 80,000 N/mm2
8154.9 kg/ mm2
.
c. Variable Spring Hanger or Variable Effort Support:
Variable effort supports as shown in figure 2.3 also known as variable hangers or variables are
used to support pipe lines subjected to moderate (approximately up to 50mm) vertical thermal
movements. VES units (Variable effort supports) are used to support the weight of pipe work or
equipment along with weight of fluids (gases are considered weightless) while allowing certain
quantum of movement with respect to the structure supporting it. Spring supports may also be
used to support lines subject to relative movements occurring typically due to subsidence or
earthquakes. A VES unit is fairly simple in construction with the pipe virtually suspended
directly from a helical coil compression spring as the cut away sectional sketch shows below.
The main components being: (Werner Sölken, 2008-10).
Top Plate
1. Pressure plate or Piston Plate.
2. Bottom plate or base plate
3. Helical Spring
4. Turnbuckle assembly
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5. Locking Rods
6. Name Plate
7. Can section or cover
Normally Clients / Engineering Consultants will furnish the following data when issuing
enquires for Variable effort units. (Werner Sölken, 2008-10).
1. Hot Load
2. Thermal Movement (with direction i.e. up or + & down or -)
3. Maximum Load variation in Percentage (LV % max), if Max LV is not specified then it
is assumed to be 25% as per MM-SP58.
4. Type of Support i.e. whether hanging type, foot mounted type etc.
5. Special features such as travel limit stop required if any.
6. Preferred surface protection / Paint / Finish.
Hot load is the working load of the support in the “Hot” condition i.e. when the pipe has traveled
from the cold condition to the hot or working condition. Normally MSS-SP58 specifies max
Load Variation ( popularly called LV) as 25%. (Werner Sölken, 2008-10).
Salient Features-
• Allows movement in vertical direction
• Load on pipe varies with movement
Used where
• Displacement < 50mm
• Load variability < 25%
• Rod angulation should be less than 4°
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Load Variation (LV) or Percentage variation = [(Hot Load ~Cold Load) x 100]/Hot Load or
Load Variation (LV) or Percentage variation = [(Travel x Spring Rate) x 100]/Hot Load
Generally spring supports are provided from top but due to layout feasibility or any other reason
Base Mounted type support is fixed to floor or structure & the pipe is made to “sit” on top of the
flange of the spring support. (Rice University,2004)
d. Constant Spring Hanger or Constant Effort Support:
When confronted with large vertical movements typically 150 mm or 250 mm, there is no choice
but to select a constant effort support (CES) as shown in figure 2.4 . When the Load variation
percentage exceeds 25% or the specified max LV% in a variable hanger, it is choice less but to
go for a CES. For pipes which are critical to the performance of the system or so called critical
piping where no residual stresses are to be transferred to the pipe it is a common practice to use
CES. In a constant effort support the load remains constant when the pipe moves from its cold
position to the hot position. Thus irrespective of travel the load remains constant over the
complete range of movement. Therefore it’s called a constant load hanger. Compared to a
variable load hanger where with movement the load varies & the hot load & cold load are two
different values governed by the travel & spring constant. A CES unit does not have any spring
rate. (Rice University,2004)
e. Snubber or Shock Absorber
Dynamic Restraints: The restraint system performs an entirely different function to that of the
supports. The latter is intended to carry the weight of the pipe work and allow it to move freely
under normal operating conditions. The restraint system is intended to protect the pipe work, the
plant and the structure from abnormal conditions; it should not impede the function of the
supports. Conditions that necessitate the use of restraints are as follows – • Earthquake. • Fluid
disturbance. • Certain system functions.
• Hydraulic Snubber: Similar to an automobile shock arrestor the hydraulic snubber is
built around a cylinder containing hydraulic fluid with a piston that displaces the fluid
from one end of the cylinder to the other. Displacement of fluid results from the
movement of the pipe causing the piston to displace within the cylinder resulting in high
16

pressure in one end of the cylinder and a relatively low pressure in the other. The velocity
of the piston will dictate the actual difference in pressure. The fluid passes through a
spring-loaded valve, the spring being used to hold the valve open. If the differential
pressure across the valve exceeds the effective pressure exerted by the spring, the valve
will close. (Rice University,2004).
• Mechanical Snubber: Whilst having the same application as the hydraulic snubber,
retardation of the pipe is due to centrifugal braking within the snubber. A split flywheel is
made to rotate at high velocity causing steel balls to be forced radially outwards..
• A shock absorber absorbs energy of sudden impulses or dissipates energy from the
pipeline. For damper and dashpot, see Shock absorber
An insulated pipe support (also called pre-insulated pipe support) as shown in plate 2.6 is a
load-bearing member and minimizes energy dissipation. Insulated pipe supports can be designed
for vertical, axial and/or lateral loading combinations in both low and high temperature
applications. Adequately insulating the pipeline increases the efficiency of the piping system by
not allowing the "cold" inside to escape to the environment For insulated pipe, see Insulated
pipe.(Rice University,2004).
An engineered spring support upholds a specific load, including the weight of the pipe,
commodity, flanges, valves, refractory, and insulation as shown in plate 2.6. Spring supports also
allow the supported load to travel through a predetermined thermal deflection cycle from its
installed condition to its operational condition. (Rice University,2004).
• Materials
Pipe supports are fabricated from a variety of materials including structural steel, carbon steel,
stainless steel, galvanized steel, aluminum, and ductile iron. Most pipe supports are coated to
protect against moisture and corrosion as shown in plate 2.7r. Some methods for corrosion
protection include: painting, zinc coatings, hot dip galvanizing or a combination of these. (Rice
University,2004).
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f. Standards
a. Design: ASME B31.1, ASME B31.3, ASME Section VIII Pressure Vessels
b. Manufacturing: MSS-SP58 (Material, Design, Manufacture, Selection, Application &
Installation), MSS-SP69 (Selection & Application), MSS-SP77, MSS-SP89, MSS-SP90,
AWS-D1.1, ASTM-A36, ASTM-A53, ASTM-A120, ASTM-A123 and A446, ASTM-
A125, ASTM-A153, ASTM-307 and A325, ASTM-C916, ASTM-D1621, ASTM-
D1622, ASTM-D1623
c. Quality Systems: ISO 9001, ASQC Q-92, CAN3 Z299
d. Testing: ANSI B18.2.3
2.1.5 Sling (steel wire rope).
Wire rope is a type of cable which consists of several strands of metal wire laid (or 'twisted') into
a helix. The term cable is often used interchangeably with wire rope. However, in general, wire
rope refers to diameters larger than 3/8 inch. Sizes smaller than this are designated as cable or
cords. Initially wrought iron wires were used, but today steel is the main material used for wire
ropes.Historically wire rope evolved from steel chains which had a record of mechanical failure.
While flaws in chain links or solid steel bars can lead to catastrophic failure, flaws in the wires
making up a steel cable are less critical as the other wires easily take up the load. Friction
between the individual wires and strands, as a consequence of their twist, further compensates
for any flaws. (Lipsett, A.W. 1985)
• History
Modern wire rope was invented by the German mining engineer Wilhelm Albert in the years
between 1831 and 1834 for use in mining in the Harz Mountains in Clausthal, Lower Saxony,
Germany. It was quickly accepted because it proved superior to ropes made of hemp or to metal
chains, such as had been used before. Wilhelm Albert's first ropes consisted of three strands
consisting of four wires each. In 1840, Scotsman Robert Stirling Newall improved the process
further. In the last half of the 19th century, wire rope systems were used as a means of
transmitting mechanical power including for the new cable cars. (Kirk and Sullman, 2001).
18

• Wires
Steel wires for wire ropes are normally made of non-alloy carbon steel with a carbon content of
0.4 to 0.95%. The tensile forces and to run over sheaves with relatively small diameters.
• Strands
In the so-called cross lay strands, the wires of the different layers cross each other. In the mostly
used parallel lay strands, the lay length of all the wire layers is equal and the wires of any two
superimposed layers are parallel, resulting in linear contact. The wire of the outer layer is
supported by two wires of the inner layer. These wires are neighbors along the whole length of
the strand. Parallel lay strands are made in one operation. The endurance of wire ropes with this
kind of strand is always much greater than of those (seldom used) with cross lay strands. Parallel
lay strands with two wire layers have the construction Filler, Seale or Warrington. (Sarpkaya, T.
& Isaacson, M. 1981)
• Spiral ropes
In principle, spiral ropes are round strands as they have an assembly of layers of wires laid
helically over a centre with at least one layer of wires being laid in the opposite direction to that
of the outer layer as shown in plate 2.9 and 2.10. Spiral ropes can be dimensioned in such a way
that they are non-rotating which means that under tension the rope torque is nearly zero.
(Werner Sölken , 2008-10 ):
• Stranded ropes
Stranded ropes are an assembly of several strands laid helically in one or more layers around a
core. This core can be one of three types. The first is a fiber core, made up of synthetic material.
Fiber cores are the most flexible and elastic, but have the downside of getting crushed easily. The
second type, wire strand core, is made up of one additional strand of wire, and is typically used
for suspension. The third type is independent wire rope core, which is the most durable in all
19

types of environments. Most types of stranded ropes only have one strand layer over the core
(fiber core or steel core). The lay direction of the strands in the rope can be right (symbol Z) or
left (symbol S) and the lay direction of the wires can be right (symbol z) or left (symbol s). This
kind of rope is called ordinary lay rope if the lay direction of the wires in the outer strands is in
the opposite direction to the lay of the outer strands themselves. If both the wires in the outer
strands and the outer strands themselves have the same lay direction, the rope is called a lang lay
rope (formerly Albert’s lay or Lang’s lay). Multi-strand ropes are all more or less resistant to
rotation and have at least two layers of strands lay helically around a centre. The. (Chakrabarti,
S. K. 2002)
• Classification of ropes according to usage
Depending on where they are used, wire ropes have to fulfill different requirements. The main
uses are:
a. Running ropes (stranded ropes) are bent over sheaves and drums. They are therefore
stressed mainly by bending and secondly by tension.
b. Stationary ropes stay ropes (spiral ropes, mostly full-locked) have to carry tensile forces
and are therefore mainly loaded by static and fluctuating tensile stresses. Ropes used for
suspension are often called cables.
c. Track ropes (full locked ropes) have to act as rails for the rollers of cabins or other loads
in aerial ropeways and cable cranes. In contrast to running ropes, track ropes do not take
on the curvature of the rollers. Under the roller force, a so-called free bending radius of
the rope occurs. This radius increases (and the bending stresses decrease) with the tensile
force and decreases with the roller force.
d. Wire rope slings (stranded ropes) are used to harness various kinds of goods. These slings
are stressed by the tensile forces but first of all by bending stresses when bent over the
more or less sharp edges of the goods. (Borgman, L.E. 1967)
• Safety
20

The wire ropes are stressed by fluctuating forces, by wear, by corrosion and in seldom cases by
extreme forces. The rope life is finite and the safety is only given by inspection for the detection
of wire breaks on a reference rope length, of cross-section loss as well as other failures so that
the wire rope can be replaced before a dangerous situation occurs. Installations should be
designed to facilitate the inspection of the wire ropes. (Chakrabarti, S. K. 1994)
Lifting installations for passenger transportation require that a combination of several methods
should be used to prevent a car from plunging downwards. Elevators must have redundant
bearing ropes and a safety gear. Ropeways and mine hoisting must be permanently supervised by
a responsible manager and the rope has to be inspected by a magnetic method capable of
detecting inner wire breaks. (Chakrabarti, S. K. (ed) 1987)
• Terminations
The end of a wire rope tends to fray readily, and cannot be easily connected to plant and
equipment. There are different ways of securing the ends of wire ropes to prevent fraying. The
most common and useful type of end fitting for a wire rope is to turn the end back to form a loop.
The loose end is then fixed back on the wire rope. Termination efficiencies vary from about 70%
for a Flemish eye alone; to nearly 90% for a Flemish eye and splice; to 100% for potted ends and
swaging. (Davenport, A.G. 1964)
• Thimbles
When the wire rope is terminated with a loop, there is a risk that it will bend too tightly,
especially when the loop is connected to a device that spreads the load over a relatively small
area. A thimble can be installed inside the loop to preserve the natural shape of the loop, and
protect the cable from pinching and abrading on the inside of the loop as shown in plate 2.11.
The use of thimbles in loops is industry best practice. The thimble prevents the load from coming
into direct contact with the wires. (Dean R. G. & Dalrymple, R. A. 1991)
• Wire rope clamps/clips
A wire rope clamp, also called a clip, is used to fix the loose end of the loop back to the wire
rope. It usually consists of a U-shaped bolt, a forged saddle and two nuts. The two layers of wire
21

rope are placed in the U-bolt. The saddle is then fitted over the ropes on to the bolt (the saddle
includes two holes to fit to the u-bolt). The nuts secure the arrangement in place. Three or more
clamps are usually used to terminate a wire rope. As many as eight may be needed for a 2 in
(50.8 mm) diameter rope. There is an old adage; be sure not to "saddle a dead horse." This means
that when installing clamps, the saddle portion of the clamp assembly is placed on the load-
bearing or "live" side, not on the non-load-bearing or "dead" side of the cable. (Wikipedia,2014).
• Waged terminations
Swaging is a method of wire rope termination that refers to the installation technique. The
purpose of swaging wire rope fittings is to connect two wire rope ends together, or to otherwise
terminate one end of wire rope to something else. (DNV-OS-C101, 2004)).
• Wedge sockets
A wedge socket termination is useful when the fitting needs to be replaced frequently. For
example, if the end of a wire rope is in a high-wear region, the rope may be periodically
trimmed, requiring the termination hardware to be removed and reapplied. An example of this is
on the ends of the drag ropes on a dragline. The end loop of the wire rope enters a tapered
opening in the socket, wrapped around a separate component called the wedge. The arrangement
is knocked in place, and load gradually eased onto the rope. As the load increases on the wire
rope, the wedge becomes more secure, gripping the rope tighter. (Chakrabarti, S. K. (ed) 2005).
• Potted ends or poured sockets
Poured sockets are used to make a high strength, permanent termination; they are created by
inserting the wire rope into the narrow end of a conical cavity which is oriented in-line with the
intended direction of strain. The individual wires are splayed out inside the cone, and the cone is
then filled with molten zinc, or now more commonly, an epoxy resin compound. (DNV-OS-
C105, (2005):
• Eye splice or Flemish eye
An eye splice as shown in plate 2.12 may be used to terminate the loose end of a wire rope when
forming a loop. The strands of the end of a wire rope are unwound a certain distance, and plaited
22

back into the wire rope, forming the loop, or an eye, called an eye splice. When this type of rope
splice is used specifically on wire rope, it is called a "Molly Hogan", and, by some, a "Dutch"
eye instead of a "Flemish" eye. (API, 1984).
2.1.6 Saddle clamp
Saddle clamps are useful hardware that allow builders and remodelers to set tubes, pipes and
other fixtures into place, and to attach tubular fittings and fencing panels together. They come in
various forms, are usually made of strong aluminum or stainless steel, and include fastening
plates that are set with a pair of threaded bolts. Saddle clamps are most commonly used on
electrical conduit, antenna poles and plumbing fixtures. (M.Rajagopal , 2010)
• Sizing
Using the proper size of saddle clamp is vital to successful installation. Saddle clamps are
measured in inches and by diameter, corresponding to the width of the fixture to which they will
be attached. Too large a saddle clamp, and your fixtures will not be firmly attached. Too small,
and they will not fit and will eventually fail altogether. (Newland, D.E. 1975)
• Material
Choosing the proper material is also key. Saddle clamps come in iron, brass, steel, aluminum and
polyvinyl chloride (PVC). Although stainless steel will not rust, it is prone to slippage when
applied to plastic fittings. Aluminum is a lighter material that is appropriate for outdoor
installations such as fencing and antennas. PVC clamps are cheap and easy to work with.
(Sarpkaya, T. 1976)
• Installation
Installers have to provide enough clamping strength to keep the fixtures in place. This means
using multiple clamps if necessary, especially if working on outdoor fixtures that will be subject
to wind and weather. Multiple clamps must be evenly spaced along the entire length of the
fixture to be clamped, and not bunched at one end or another. (Wheeler, J.D. 1970)
23

• Glue-on Saddle Clamps
Saddle clamps can also be useful for tapping into an existing water line. The user drills a hole
into the line, fits the clamp over the hole, and glues it into place. There is an outlet in the clamp
to which a new line can be fitted. There is no need to cut a T-joint into the old line and fit gaskets
or corrodible metal parts in place.( OFFSHORE VN 31 October 2013)
• Tightening
To fasten the saddle clamp, you need to apply a torque wrench to a set of two or more fastening
bolts as show in figure 2.5. The torque has to be uniform across the entire clamp, otherwise the
fastener will seize up and the surfaces of the tube or pipe will be degraded. Use of a lubricant on
the bolt threads and to both sides of the washers while installing will help keep the bolts from
seizing. (M.Rajagopal , 2010)
2.1.7 Spreader beam:
Spreader beams lift loads with single or multiple attachment points as shown in figure 2.6. They
handle a variety of loads such as long bundles, rolls, cylinders, and machinery. Spreader beams
are designed for safety, durability and simple operation. We have significant experience
designing and building lifting and spreader beams for use in primary steel mills, steel service
centers, pulp and paper mills, power plants and in difficult with varied crane layouts.
All spreader beams are designed and manufactured in accordance with the latest revision of
ASME Spec. B30.20 and BTH-1: Design of Below-the-Hook Lifting Devices.
Five basic spreader beam models are available in many different design configurations.
• Model 413 a spreader beam with formed hooks for use with slings.
• Model 415 a spreader beam with plate hooks to engage a shaft or mandrel, used primarily
for handling paper rolls.
• Model 420 the positions of the hooks on this spreader beam are adjustable to
accommodate different load lengths.
• Model 439 a basic spreader beam with safety swivel hooks for use with slings or chains.
24

• Model 490 a chlorine cylinder lifting beam. (Modulelift, 2013)
1. How to Design a Spreader Bar
The approach to optimizing the designing of the spreader bar design (otherwise known as lifting
bar or lifting beam) is an iterative process. Variations in the design of the multi-lift spreader bar
evolve over a period of time as requirements and technology change and the demand for a more
efficient product is desired.These spreader bars generally have one structural member down the
center with hooks off the bottom to suspend a load. They also include either one or two hooks off
the top to attach to a spreader bar. The idea is to distribute the load over the beam so you can
pick up large items with vertical slings and only one crane.Lifting beams (also known as
spreader beams) are used to assist in the hoisting process. Most erectors and riggers accumulate
an assortment of lifting beams during the course of time. (Modulelift,2013).
1.. Single Spreader Beam: 2-point Lift
2. Single Spreader Beam: 4-point Lift
3. 3 Spreader Beams – 1-over-2: 4-point Lift
4. 3 Spreader Beams – 1-over-2 in-line: 4-point Lift
5. 2 Spreader Beams – 1-over-1: 3-point Lift
6. Multiple Spreader Beams: Multi point Lift
7. Spreader Frames
8. Lifting Frames
25

26
Figure 2.1: A MOUSED SHACKLE (Hiscock, Eric C. 1965).
Figure 2.2: 3D ISOMETRIC VIEW OF A PADEYE. ( Sarpkaya, T. & Isaacson, M. 1981)
Figure 2.3: Variable spring hanger (M.Rajagopal, 2010)

27
Figure 2.4: Bell crank in CSH( M.Rajagopal,2010)
Figure 2.5: Typical sections of saddle clamp for pipe support (sea fastening.)
(Modulelift, 2013)
Figure 2.6: How to Design a Spreader Bar (Modulelift,2013).

28
PLATE 2.1: A TYPICAL QUAYSIDE CRANE LIFTING A STRUCTURAL MEMBER
ONTO A VESSEL. (Graff, W. J., 1981)
PLATE 2.2: A SNAP SHACKLE SPLICED TO A LINE. (Hiscock, Eric C. 1965).
PLATE 2.3: TYPICAL SECTION OF A PAYEYE WELDED ON A BEAM (www.liftmax.com)

29
Plate 2.4 : Pipe Guides (Cylinder Pipe Guides - Spider Guides)( M.Rajagopal,2010)
Plate 2.5: Pipe Anchors (Permali Cold Shoes) (M.Rajagopal, 2010)
Plate 2.6: Insulated Supports (Cold Shoes) ( M.Rajagopal,2010)

30
Plate 2.7: Engineered Spring Supports (Variable Springs) ( M.Rajagopal,2010)
Plate 2.8: Shock Absorber (Hydraulic) ( M.Rajagopal,2010)
Plate 2.9: Left-hand ordinary lay (LHOL) wire rope (close-up). Right-hand lay
strands are laid into a left-hand lay rope.

31
Plate 2.10: Right-hand Lang's lay (RHLL) wire rope (close-up). Right-hand lay
strands are laid into a right-hand lay rope.
Plate 2.11: Right-hand ordinary lay (RHOL) wire rope terminated in a loop with a
thimble and ferrule.
Plate 2.12: The ends of individual strands of a eye splice.

CHAPTER THREE
3.0 METHODOLOGY
3.1 DELIEVERABLES FOR THIS PROJECT.
• Theory
• Installation Procedure
• Design of Spreader bars for lifting the caisson from the quayside onto crane barge.
• Caisson Sea fastening Design Calculation
• Lifting Analysis for installing the caisson onto the FPSO in the gulf of guinea..
3.1.1 Theory.
• Hook loads
Loads in lift rigging and the total loading on the crane hook(s) should be based on hook loads
defined as below, where:
Static Hook load = (Gross Weight or NTE weight) + (Rigging Weight)
Dynamic Hook load = Static Hook load x DAF
Rigging weight includes all items between the lift points and the crane hook, including slings,
shackles and spreader bars or frames as appropriate.
For twin hook lifts whether cranes are on the same vessel, or multiple vessels, or the structure is
suspended from two hooks on the same crane on the same vessel.
• Lift point loads
The basic vertical lift point load is the load at a lift point, taking into account the structure Gross
weight proportioned by the geometric distance of the centre of gravity from each of the lift points
(if they are all at the same elevation). The basic lift point load is further increased by the factors
as listed in Figure 3.1 as appropriate for the lifting arrangement under consideration.
If the lift points are at different elevations as shown in Figure 3.1 then sling forces shall be
resolved at the sling intersection point, IP, which will be above the hook (if connected directly to
32

the hook) or, if connected to a shackle /sling system suspended from the hook, the IP will be
above the connection point on the shackle. The design sling loads should consider a CoG
envelope and the loads in the slings determined by positioning the extremes of the CoG envelope
under the IP and the sling loads recalculated using the new sling angles α and β.
• Sling loads
The sling load is the vertical lift point load resolved by the sling angle to determine the direct
(axial) load in the sling and lift point using the minimum possible sling angle. The sling angle
should not normally be less than 60º to the horizontal although for lifts that are installed at an
angle this may not be the case, e.g. flare booms installed by a single crane, the upper rigging may
be less than 60º. For lift point design, the rigging weight shall not form part of the lift point load.
• Dynamic amplification factors
Unless operation-specific calculations show otherwise, for lifts by a single crane in air, the DAF
shall be derived from the following Table 3.1.
3.1.2 DESIGN BASIS
• SPREADER BAR
Weight, w
Factor of safety, F.S
Materials (Universal beam, I Beam) Section
Yield Strength, fy
Modulus Of Elasticity, E
Dimension
Length of the beam, l
Depth of the section, d
Width of the section, h
33

Width of the compression flange, b
Thickness of the compression flange, t
Area of the compression flange, Af= b*t
Minor axis radius of gyration, ry
Second moment of area, Ixx
COMPACT SECTION CHECK
b/t …………………………………………………….. ……………….(1)
0.38* (E/fy)0.5
…………………………………………………………. (2)
Check
b/t< 0.38* (E/fy)0.5
…………………………………………………….. (3)
BENDING STRESS CHECK
Allowable bending stress,fb
fb = 1.1 x
F
F
s
y
………………………………………………………… (4)
Bending moment, m
m =
4
wl
………………………………………………………… (5)
Actual bending stress, s
S =
xx
cm
1
×
………………………………………………………… (6)
Check S < fb ………………………………………………………… (7)
34

• LIFTING LUGS DESIGN
Parameters
Yield stress of pad eye, Fy
Pin Hole Diameter, d1
Cheek Plate Radius, r1
Main Plate Radius, r2
Main Plate Thickness, T2
Sling Angle to the Horizontal, Ø
Pin diameter is 5 mm less pin hole diameter,dp
Pad eye width, bw
Minimum radius of the main plate is the Max. value between 1.25d1 or d1/2 + 3 …………. (8)
Adopt radius of Main plate r2
Max. Module Weight, (w)
API RP 2A Factor of safety, f.s
Assume Structure is fairly evenly loaded about centerline
Converting W from Tons to KN
35
R1 R2
R3
60o
60o
Length of sling
Spreader bar
Length of
beam
2
w
2
w

Obtain sling forces by resolving the forces (R1, R2, R3)
Tension on the sling = R3
Maximum sling force, Fs = R3
Degisn pad eye force, Ps = 1.2 X P X 10 ………………………………. (9)
Bearing Stress Check
Actual bearing plate thickness, tb = (2T1+T2)
Area required, Areq = Ps / 0.9 fy …………………………. …..(11)
Thickness required, treq = Areq / dp
Actual bearing stress,fB = Ps/(dp(T2+2T1)
Allowable bearing stress = 0.9 fy …….…………………………. …..(14)
Check: If actual bearing stress < allowable bearing stress …………… (15)
Tear out Shear Stress Check
Tear out shear area, fS = 4T1(r1/2-d1/2) + 2T2(r2 - d1/2) …………….. (16)
Actual Shear Stress, fA = Ps / fS ………………………………………………….. (17)
Allowable Shear Stress =0.4Fy ………………………………………………….. (18)
Check: Actual bearing stress < allowable bearing stress …………… (19)
Tensile Stress Check
Allowable stress on the met area of the pin hole for
Pin connected member, FT = 0.45fy ……………………………… (20)
Pin hole cross sectional area, pAs = T2(2r2-d1) + 2T1(2r1-d1) ……………………… (21)
36

Sling vertical load component including 5% impact factor,
Pvs = 5% R3 + R3 ……………………………………………………………….… (22)
Allowable tensile stress,fallow = fT x pAs …………………………………….……... (23)
Actual tensile stress, factual = Pv / pAs …………………………………………….. (24)
Check: If facial < fallow …………………………………………. ……………… (25)
Combines stress (Axial and bending)
Area of pad eye, Ap = T2 x bw …………………………………………. ………… (26)
section modulus of the major axis, S1 = 1/6 T2bw
2
…………………………………. (27)
section modulus of the minor axis, S2 = 1/6 T2
2
bw …………………………………. (28)
pad eye axial stress, Pvs / Ap …………………………………..………………………………... (29)
sling horizontal load component including 5% impact factor, Phs
R1 Cosθ or R2 Cosθ + 5% R1 ……………………………………………… (30)
center of hole to fixed edge, h1
center of hole to centroid of lifting section distance, h2
bending stress-major axis, Fbx = (Pvs x h2 - Phs x h1)…………..………………………… (31)
In plane shear stress due to horizontal loading, fsh = Phs/T2bw …………………… (32)
5% impact factor sling vertical load component, Pn = 5% X R3 ……………………. (33)
Minor axis bending stress,fbz1 = Pn x (h1/S2) ………….…………..…………………………. (34)
Unity check: U = 




 +++
fy
FFFF lbbbxa
6.0
222
+
2
6.0 







y
sh
F
F
< 1 ……………………… .. (35)
Cheek Plate Weld Check
37

cwσ = Ps X
( )arT
T
t ×× 1
1
2
………………………………...…………………………… (36)
weld thickness, s
throat of fillet weld, a = 0.7s………..………………………………...…………………(37)
Stress on cheek plate weld,w = s x σcw…………………………...…………………….(38)
Ultimate strength, Fu
Correlation factor, βw
Partial factor of resistance of plate in bearing, γM2
Design strength of weld, Fviod =
( )
( )2
3
mw
Fn
γβ ×
………………………...…………………(39)
Design strength of well per unity length, foro = fviod x a ………………………………. (40)
Check:
( )
( )cw
Fviod
σ×5
< 1 …………………………….………………………………. (41)
Weld Of Plates to Padeye Main Plate
Assume load on weld, Lw
Minimum weld of padeye plate, with resistance factor
Tweld =
( )
( )cw
w
FL
L
×
Provide weld size
3.1.3 DESRIPTION OF THE FIELD IN THE GULF OF GUINEA
The FPSO (Floating Production Storage and Offloading) facility is located in OPL 212 offshore
Nigeria, in the Gulf of Guinea, water depth approximately 1,000 meters as shown in plate 3.2
and figure 3.2. The oil field utilizes a water flooding system to produce the oil with water being
38

pumped into the reservoir via subsea injection wells and the oil being extracted via other subsea
production wells.
The water flooding system requires sea water to be pumped in using submerged pumps installed
in caissons 63 meter long hanging through guides welded to the hull of the FPSO. The sea water
passes through a bank of 8 Multimedia and 4 Cartridge filters before being injected into the
reservoir. Currently there are 2 electrically driven submerged centrifugal pumps each delivering
1,325 m3/Hr .at 12.4 Barg, (A total of 400,000 BWPD). This represents 75% of the required
injection flow, the balance being made up by produced water.
In order to sustain the water flooding capacity, a third pump is required to be installed. This will
ensure water flooding capacity and provide flexibility for maintenance work on the pumps. The
caisson guides for the third pump were installed on the FPSO alongside the two existing caissons
during construction before sail out. The materials procured for the new caisson is 36 inch OD
and varying wall thicknesses; have excessive ovality and curvature along the length on the
individual joints. Some of the ovality is due to joints of pipe being cut, to develop the required
wall thickness profile along the length of the caisson. (The centre sections of joints of line pipe
are not fabricated to the same roundness mill tolerance’s’ as the pipe ends).
The heavier wall thickness is located at the splash zone area which is more susceptible to
corrosion. In extending the life of an asset it is essential to demonstrate integrity at all levels and
comply with standards, which include verification and assurance of aging assets to protect the
environment.
3.1.4 Caisson Material
 API 5L X52 Line Pipe Physical Properties
 Line pipe grade designations come from API Spec 5L Specification for Line Pipe.
Standard Line Pipe has grade designation A and B. Stronger grades have the designation
X followed by the specified minimum yield strength of the pipe steel, measured in kilo
pounds per square inch (abbreviated ksi).
 Yield Strength = 52000N/m2
 Elongation Factor= 21%
39

 Tensile Strength = 66000N/m2
Table 3.2 represents the caissons computational weight.
Allow for 10% contingency for bolts and other fittings = 1.1 x 41.399/10 = 45 tons
Square top flange of 1.5m x1.5m x 0.07m thick = 875kg
Hanger Flange = 250kg
Total self weight of the flanges = 1.2 tons.
3.1.5 INSTALLATION PROCEDURE
The purpose is to;
• Define a Lifting Plan and its Implementation Methods.
• Ensure that the activities as outlined in this Procedure are conducted in a safe
manner without endangering life or property (which may result from a failure).
3.1.6 REFERENCES, CODES AND STANDARDS
• CODES AND STANDARDS
In general, this Mechanical Lifting Procedure is in compliance with applicable Codes and
Standards binding on the offshore oil and gas industry.
• INTERNATIONAL STANDARDS
1. API RP-2D, “Recommended Practice for Operation and Maintenance of
Offshore; Cranes”, 5th edition, June, 2003.
2. ASME B30.20, “Below-the-Hook Lifting Devices”, 2006
3. BS 5744, “Code of Practice for Safe Use of Cranes”, 1979
• NIGERIAN STANDARDS
40

1. The Factories Decree, 1987 (also known as “The Factories Act”)
2. The Lifting Operations and Lifting Equipment Regulations, 1988, No. 2307,
paragraphs 9, 10 and 11
3. Health and Safety at Work Act, 1974
3.2 LIFTING PLAN
Mechanical lifting operations to be performed on the FPSO shall be risk-assessed and planned
with specific attention to the inherent hazards. No operation shall be initiated before the full
implementation of all preventive and mitigating controls.
Every lifting operation must be risk assessed by a competent person before it is carried out.
Installation Contractor shall use the rule of task planning to ensure that hazards are identified and
appropriate controls are in place, so as to reduce the likelihood and consequences of incidents
The important factors to be considered first for successful operation are;
• The Lift plan is properly defined.
• The competency of the personnel carrying out the work should be sufficient
for the task to be undertaken
• The Lift is planned to ensure that all hazards have been identified, risk
managed with appropriate measures implemented to control these risks
• Ensure that the lifting is carried out with suitable equipment in accordance
with the well-defined Plan
The Lift Plan is intended to clearly identify the competent person(s) planning the Lift, the step-
by-step lifting operation, the equipment required and the activity assigned to each.
The stabbing of the cruciform point on the lower section of the caisson, into the top stabbing
guide is the activity with most risk. The internal diameter of the guide is 940 mm; the
“diameter” of the stabbing point is 320 mm. To lower the caisson (or caisson section) into the
guide is a delicate operation, to compensate for the removal of the centraliser the stabbing point
can be extended to make it longer and smaller at the point. Taking into consideration the fact
41

that the movement of the FPSO is negligible and the lifting will take place during a good weather
season the stabbing of the caisson will not be a problem. RISK LEVEL “As Low As Reasonable
Practicable, ‘’ALARP”.
3.2.1 CAISSION LOAD OUT TO QUAYSIDE
The fabricated caissons shall be loaded out from the fabrication yard Yard Agege to a suitable
quayside in Lagos for final welding of the 8 No’s pipes to achieve single length of 63m.
3.2.2 QUAYSIDE TO BARGE
• Weld the 8Nos caisson strings into one 63 m length.
• Design and fabricate the spreader bars, lifting lungs and sling wires
• Weld lifting lungs to the caisson.
• Design and Fabricate the sea fastening structural supports and clamps to hold
the caisson in place during sea transportation.
• Loading out of the Caisson from the quayside with the quayside crane and
spreader bar onto the vessel.
• Fasten clamps with bolts.
• Cut off welded lifting lungs and smoothen surface.
• Sail to the FPSO.
3.2.3 SAIL TO FPSO FOR INSTALLATION
• Position vessel on FPSO starboard side ready for installation
• Remove sea fastening clamps.
• Up-end caisson using crane main boom from the top flange pad eyes.
• At 300
support the caisson with whip-line at mid-point to reduce the
likelihood of deflection.
42

• With the aid of the pad eye and fulcrum system designed at the other end of
the caisson, the caisson can easily rotate about the axis making lifting operation easy and
safe.
• When vertically erect, the caisson can be pulled out of the clamp.
• Install Caisson into the guides on the FPSO.
3.2.4 INSTALLING TO THE FPSO
• Position the crane barge 25m minimum from the FPSO.
• Remove sea fastening clamps.
• Up-end caisson using the main boom from the top flange pad eye.
• At 300
from the horizontal support caisson at mid span with the whip-line.
• The fulcrum system designed at the other end ease up-ending vertically.
• Boom crane to install to FPSO.
3.2.5 LOADOUT SEQUENCE FROM CRANE BARGE ONTO THE FPSO IN THE
GULF OF GUINEA.
Table 3.3 to Table 3.7 represents the loading sequence from the Crane Barge onto the FPSO.
Since the caisson is fastened on the deck of the crane barge and pivoted at one end, so as
to enable the crane to boom and install onto the FPSO.
3.2.6 SPECIFICATION FOR LIFTING EQUIPMENT AND ACCESSORIES
• Crane
Lifting equipment specifically include lifting gear and lifting appliance.
Crane should be able to lift 50,000 Kg at a distance of 20-30m distance from the edge of its own
deck at a hook height of 85-90 m above sea level.
Lifting Gear is any device that is used for, or designed to be used directly or indirectly, to
connect a load to a lifting appliance (for example crane or chain block).
Lifting equipment must be used only for the specific purpose for which it was designed.
43

Personnel involved in lifting operation or interpretation of lifting gear must have full knowledge
of NDE. For the purpose of interpretation and examination, the personnel involved in the task
should be qualified in accordance with the requirement of BS5744 or equivalent.
• Shackles
An important commonly used component in a lifting system is a shackle.
There are several types and variations for shackles but the common ones are;
• Screw pin shackle
• Bolt type or safety shackle
Safety shackles (with screw pin and cotter pin) should be used on lifting gear for heavier lifts.
In accordance with the Strength Check Report for Pad eye and Lifting in Chapter four, the
shackles to be employed shall be the Crosby 2-1/2” x 55 ton SWL Screw pin type.
• Sling Wire Rope
The sling wires shall be inspected and proof load re-certified at six month intervals. Slings shall
be rejected if on visual examination, they are found to have the following defects;
• Bird caging
• Crushed wire rope
• Kinking
• Discoloration
• Visibly broken wires
If broken wires are visible in the wire rope then the minimum number of broken wires for
rejection of the wire rope is given in terms of a formula;
“For a length of eight (8) times the wire rope diameter, only 10% of the total number of wires
can be broken wires”.
44

The sling wire for the load test shall be in accordance with the Strength Check Report for Pad
eye and Lifting in chapter four
The crane barge chosen to transport the caisson to the FPSO in the gulf of guinea is a pipe lay
construction vessel built according to the Group’s hybrid design philosophy featuring DP3, a
large unobstructed main deck, a big crane and large scale offshore accommodation capacity.
• SPECIFICATION OF THE CRANE BARGE.
Plate 3.2 represents a typical Crane Barge to be choosen to transport having in mind meteocean
data of given field. Also plate 3.3 represents a the deck area where the caisson will be fastened
to.
1. General
• Classification- ABS X A1 Barge ⓔ, X PAS, X DPS-3, CRC
• Flag Gibraltar
• Call sign ZDJL7
• IMO number 8770273.
2. Principal dimensions
• Length overall 118.80 m
• Breadth 30.40 m
• Extreme breadth 36.40 m
• Depth 8.40 m
• Draft (max) 4.98 m
• Draft (max) including retr. (3.10 m) thrusters 8.08 m
• Gross tonnage 14725 t
• Net tonnage 4605 t
• Deadweight (summer) 9278 t.
• Displacement (summer) 19291 t
3. Cranage
• Main crane (Huisman Itrec) - 800 mTon @ 30 m over the stern in sheltered waters and
revolving at a radius of 26 m
45

• Whip hoist - 120 mTon @ 33.50 m 3-fall config. 100 mTon @ 39.00 m 2-fall config.
Heave compensation in 2 and single fall configuration.
• Auxiliary deck crane Pedestal type, 34 t @ 20 m, 22 t @ 30 m, make TTS
4. Deck space
• Approx. 525 - 1350 m²
• Deck load - 10 t / m²
46

47
Figure 3.1 Resolving sling loading
Figure 3.2: Location of the Field
Figure 3.3: THE POSITION AT THE DECK OF THE CRANE BARGE STEP 1

48
Figure 3.4: THE POSITION 30o
TO THE DECK OF THE CRANE BARGE STEP 2
TO THE DECK OF JASCON 34 STEP 3

49
TO THE DECK OF THE CRANE B STEP 4
Figure 3.7: CRANE BOOMING TO INSTALL CAISSON ONTO THE FPSO IN
THE GULF OF GUINEA.

Table 3.1: DAF in air
Table 3.2: Weight computation for the Caisson
Member Group Length (m) Wall Thickness
(mm)
Weight (kg)
SLG 5 Dummy
P19 6.1 19.1 2572.45
P25 12.2 25.4 6793.84
P31 3.05 31.8 2110.99
P44 3.05 44.4 2905.45
P50 9.15 50.8 9899.58
P44 6.1 44.4 5810.91
P31 6.1 31.8 4221.99
P19 16.8 19.1 7084.78
Total = 62.55 Total = 41399.99
50
Plate 3.1: Location of the Field
Plate 3.2: Crane Barge(Jascon 34 DP3)
Plate 3.3: Picture of the deck area of the crane barge
where the caisson will be sea fastened.

CHAPTER FOUR
4.0 DESIGN PROCEDURE
• Designs were carried out using Sacs 5.6, Staad.pro software and excel spreadsheet.
• Caisson was analysed at angle 30, 60 & 90 degree to ascertain possible failures during
lifting operations.
• Designs were done in accordance with all relevant codes.
• Details of the design can be seen in the final issued documents.
4.1 DESIGNING THE SPREADER BAR FOR LIFTING THE CAISSON FROM
THE QUAYSIDE ONTO THE CRANE BARGE.
This comprises of 3 spreader bar configuration connected together with the following.
• Lifting lugs or pad eyes
• Shackles.
• Slings
Table 4.1 shows the computational weight of the caisson to be lifted at the quayside to the crane
barge.
Total self weight of the flanges = 1.2 tons.
TOTAL WEIGHT OF CAISSON + FLANGE = 45 + 1.2 = 46.2 tons.
Weight of spreader bar 1 + sling + 4 pad eyes = 2 tons.
51

Weight of spreader bar 2 + sling + 4 pad eyes = 1.2 tons.
Weight of spreader bar 3 + sling + 4 pad eyes = 1.2 tons.
Weight of 4 slings + 4 pad eyes = 0.4tons.
Total weight to be lifted = 46.2 + 2 +1.2 +1.2 +0.2 = 51 tons.
4.2 SEAFASTENING DESIGN
The purpose of this design is to study the procedures used to verify the structural integrity of the
primary framing and tubular joints of the Caisson under the tow conditions. The following
design analysis was performed to verify the structural integrity of the 63mm x 36’ 3rd Caisson
to be lifted and installed to an FPSO in the gulf of guinea. The grade of steel used is API 5L
Grade X52.
All members have UC values less than 1.0 Deflections have been inspected and are within the
acceptable limits. The maximum combined UC for this tow analysis is 0.07.
Also, reactions from this analysis have been presented in this report.
The analysis was done using STAADPRO Software.
41399.99kg = 406.134k N
Total self weight of the flanges = 1.2 tons
The DAF applied to the load combination is 2.0
4.2.2 Loadings
Two post design cases are considered to analyse all structural components as listed below.
Load Case 1 – Self Weight of the Caisson
52

Load Case 2 – Weight of the square Flange and the hanger flange.
The following lifting factors have been applied to the module:
Dynamic Amplification Factor – 2.0
For unaccounted load (bolts and fittings) – 1.1
4.2.3 SEA FASTENING SUPPORT DESIGN
Caisson is supported by steel beams spaced at 10 m interval which is fastened with the aid of a
clamp as seen in the detailed drawings, this caisson and beam supports are modelled with
staadpro software and support reactions obtained.
These supports are now spaced at 20 m intervals and analysed to simulate a situation where there
is a loss of support reaction during transportation of the caisson. The results obtained shows it’s
adequate to sustain the caisson in the event of such happe
The vessel to transport the caisson has the following modeled information above.
4.3 DESIGN ANALYSIS FOR LIFTING
The design analysis was performed to verify the structural integrity of the 63mm x 36’’ Caisson
to be lifted and installed at the FPSO in the Gulf of guinea. The grade of steel used is API 5L
Grade X52.
The results presented in this calculation are for lift loading condition. The scope of this lift
analysis was to confirm the structural integrity of the Caisson including tubular to tubular joints.
The scope also includes the determination of forces to be used for the shackle selection and pad
eye design.
53

The maximum deflection at 300
is 125.5mm and the maximum deflection at 600
is 69.8mm at the
4th
joint, so to totally reduce the deflection at that point, the whip line of the crane will be
attached at that point to reduce the deflection to 6.98cm which is within acceptable limit. The
design was done using SACS 5.6
4.3.1 ENVIRONMENTAL CONDITIONS
Mean Minimum Ambient Temperature : 230
C
Minimum Ambient Temperature : 180
C
Mean Maximum Temperature : 310
C
Maximum Ambient Temperature : 410
C
Ground Temperature : 25 to 27.50
C
Black Bulb Temperature : 800
C
Humidity : 100%
Average Annual Rainfall : 3800 mm
Mean Maximum Hourly Rainfall : 100 mm
Heavy rainfall can be expected in the wet season during months of April through October.
Wind Speed : 55 km/h (max)
Wind direction is predominantly South West or North east depending on the time of year.
4.3.2 Lifting Configuration
A 1500mm x 1500 mm x 75 mm square plate identical to the top square motor mounting flange
with a lifting Pad Eye incorporated is to be fabricated and welded to the top flange prior to load
out to enable the crane barge to lift the Caisson into position. The caisson will be lifted using the
main boom connected to the top flange as shown in the picture below and the whip line
connected to the mid-point of the caisson to reduce deflection.
54

Analysis was carried out in three (3) stages of the lift.
At 300
to the Horizontal the adjusted safe working load of the sling is 77.5%
At 600
to the Horizontal the adjusted safe working load of the sling is 63.3%
Finally when it is vertically lifted the adjusted safe working load of the sling is 100%
External diameter of the Caisson = 914.4mm or 36inch
41399.99kg = 406.134 KN
Total self weight of the flanges = 1.2 tons
4.3.3 Loadings
Two post design cases are considered to analyse all structural components as listed below.
Load Case 1 – Self Weight of the Caisson
Load Case 2 – Self Weight of the Caisson with DAF.
The following lifting factors have been applied to the module:
Load case 1 and 2 were combined and a consequence factor of 1.3 applied.
Dynamic Amplification Factor, DAF – 2.0
4.4 RESULTS
55

The design and installment of the Caisson for the field in the gulf of guinea has been designed
according to relevant standard and codes. These are the following results from the deliverables.
1. Sling wires
Slings wire used for this project was utilized in two aspect of the installation procedure which
include. In table 4.8, 4.9, 4.12, 4.23 represents the spreadsheet design for the sling wire used on
all the 3 spreader bars using relevant codes and standards I was able to select a suitable sling
wire type according to the BETHLEHEM WIRE ROPE GENERAL PURPOSE
CATALOGUE(Appendix A).
• Lifting with the spreader bar from the quayside to the crane barge.
• Installing the caisson from the crane barge to an FPSO in a field in the gulf of
guinea
Lifting with the spreader bar from the quayside to the crane barge: The sling wire used for the
multiple spreader bar lifted was selected based on the safe working capacity and strength of the
wire rope. According to Bethlehem wire rope inc. general purpose catalogue classified the wire
rope suitable for the operation as 19 x 7 class of wire rope with;
• Wire grade – purple plus with extra improved plow.
• Wire rope finish – Bright i.e. no protective coating other than lubricants.
• Wire rope lay – regular lay i.e. twisted to one direction unlikely to kink.
• Wire rope core – steel core i.e. independent wire rope (IWRC).
Installing using the crane from the crane barge which will be 25m away from the FPSO and at a
minimum of 15m draft, with the aid of the wire rope, which will aid the lifting of the caisson sea
fastened and pivoted on a fulcrum: The sling wire used for the lifting from the Crane Barge onto
the FPSO was selected based on the safe working capacity and strength of the wire rope.
According to Bethlehem wire rope inc. general purpose catalogue classified the wire rope
suitable for the operation as 8 x 19 class of wire rope with;
• Wire grade – purple plus with extra improved plow.
56

• Wire rope finish – Bright i.e. no protective coating other than lubricants.
• Wire rope lay – regular lay i.e. twisted to one direction unlikely to kink.
• Wire rope core – steel core i.e. independent wire rope (IWRC).
2. Spreader bars
A spreader bar is a hook lifting device that utilizes two hooks (attaching devices) located along a
beam and the spreader beam attaches to the hoist by means of a bail. The spreader beam is used
to handle long or wide load and serves to "spread" the load over more than one lifting point. This
was used in conjunction with slings. The attached devices – lifting lugs were attached on the
spreader bars to enable the wire rope and the shackle grip the spreader bar. There consist of 3
spreader bars which will be used to enable the quayside crane lift the 63m caisson from the
quayside onto the crane barge. Table 4.2 represents the spreadsheet design for spreader bar one
with the use of relevant codes and standard I was able to come up with the material for the
spreader bar which is UB 533 X 210 X 82kg/m with yield strength of 335N/mm2
and length
25m. Table 4.3 represents the spreadsheet design for spreader bar two with the use of relevant
codes and standard I was able to come up with the material for the spreader bar which is UB 533
X 210 X 82kg/m with yield strength of 335N/mm2
and length 9m. Table 4.4 represents the
spreadsheet design for spreader bar three with the use of relevant codes and standard I was able
to come up with the material for the spreader bar which is UB 533 X 210 X 82kg/m with yield
strength of 335N/mm2
and length 9m.
3. Shackles
The shackles as shown in figure 4.4 were designed for the worst condition to enable the crane on
the crane barge lifting the caisson from the quayside to the crane barge and enabling the crane
barge install the caisson successfully onto the FPSO in the gulf of guinea. Summary of the
shackle used for the lifting from the quayside to the crane barge can be seen in the detailed
calculation report. In table 4.5 represents the spreadsheet design for the shackle used on spreader
one using relevant codes and standards I was able to select a suitable shackle type(bow shackle)
according to the CROSBY GROUP CATALOGUE(Appendix b). In table 4.6 represents the
spreadsheet design for the shackle used on spreader two upper sling using relevant codes and
standards I was able to select a suitable shackle type(bow shackle) according to the CROSBY
57

GROUP CATALOGUE. In table 4.7 represents the spreadsheet design for the shackle used on
spreader two lower sling using relevant codes and standards I was able to select a suitable
shackle type(bow shackle) according to the CROSBY GROUP CATALOGUE.
4. Pad eye
The lifting lugs or pad eyes used for this project was used in three (3) aspects.Table 4.14
represents the spreadsheet design for the padeyes to be welded on all the spreader beam
• Lifting with the spreader bar from the quayside to the crane barge.
• Fastening of the caisson during transportation, lifting and installation to the
FPSO in thr gulf of guinea.
• Installing the caisson from the crane barge to the FPSO in the gulf of guinea.
4.4.1 Lifting with the spreader bar from the quayside to the crane barge.
The lifting lugs are welded on the 3 spreader bars to enable the wire rope and shook grip onto the
63m caisson and the quayside crane can lift the 63m caisson with ease from the quayside onto
the crane barge.
4.4.2 Fastening of the caisson during transportation, lifting and installation to FPSO in the
gulf of guinea.
A fulcrum system is designed on one end of the caisson to ease up-ending, this padeye is
designed with a clamp and a screw rod in such a way to reduce friction. See sea fastening
drawing for details.
4.4.3 Installing the caisson from the crane barge to FPSO in the gulf of guinea.
Pad eyes where welded on the square flange to enable the crane barge lift the caisson with ease
when it sails from the quayside to FPSO in the gulf of guinea. After thorough analysis have been
done. A suitable pad eye has been selected and will be fabricated and welded onto the square
flange at the quayside.
4.4.4 Barge onto FPSO.
58

1. Member forces and moment
2. Joint deflections and rotation.
3. Element stress (unity check).
Discussios
Since the unity check of the members are less than 1 for the maximum loadings at 300
, 600
and
900
. Therefore the lifting design to install the caisson onto the FPSO using SACS is ok.
Discussions
From table 4.34 to 4.35 represents the deflection graph shown below in plate 4.1 and 4.2 which
is gotten from the load cases applied to the Caisson at both 30° and 60° to the fulcrum pivot,
since they are infinitesimal. The design for the lifting of the Caisson onto the FPSO in the Gulf
of Guinea is ok.
4. 5 SEAFASTENING RESULT
4.5.1 Se.a fastening support design result
• Discussions:
This design is to cover the sea fastening support for the caisson on the deck area of the Crane
Barge so as to adequately support it while the Crane Barge sails to FPSO successfully. Since the
static check result and unity check max is less than 1 for all the support, the support is adequate.
• Discussions:
This design is to cover for the worst condition in case one or more support is lost due to
hydrodynamic loading on the vessel during its sail to the FPSO. Since the unity ratio is also less
than 1, if any support is lost during the vessel sails. The sea fastening support is adequate.
59

4.6 MATERIAL TAKE-OFF
The Material Take-Off for this project as shown in table 4.42, comprises of all the material
needed for each sequence of the design for caisson. The MTO contains the length & weight of
Materials used for the lifting.. A contingency of 10% of was added to the length each member.
The MTO was generated with the aid of excel spread sheet. System International units shall be
used.
60

61
Plate 4.1: Graph of length of caisson(m) against deflection(cm)
Plate 4.2: Graph of length of Caisson(m) against Deflection(cm)

62
Figure 4.3: SECTION OF THE MULTIPLE SPREADER BAR LAYOUT TO LIFT
THE CAISSON.
Figure 4.4: TYPICAL S2130 SHACKLE

TABLE 4.1 Weight computations for Caisson for the Spreader bar configuration
Member Group Length (m) Wall Thickness (mm) Weight (kg)
SLG 5 Dummy
P19 6.1 19.1 2572.45
P25 12.2 25.4 6793.84
P31 3.05 31.8 2110.99
P44 3.05 44.4 2905.45
P50 9.15 50.8 9899.58
P44 6.1 44.4 5810.91
P31 6.1 31.8 4221.99
P19 16.8 19.1 7084.78
Total = 62.55 Total = 41399.99
63

Table 4.2 Speadsheet for spreader bar one
REF CALCULATION OUTPUT UNIT
ASME BTH-1 Weight of load, w 505215 N
ANSI/ASME B30.20- 9 Factor of safety, f.s 3
MATERIAL
ASME BTH-1 SA- 36 MATERIAL
Yield strength, fy 335 N/mm2
Modulus of elasticity E 2.00E+05 N/mm2
DIMENSION UB 533x 210X
82xkg/m
UNIVERSAL BEAMS TO BS 4: PART1:1993 Length of the beam, l 25000 mm
Depth of the section, d 528.3 mm
Width of the section, h 208.8 mm
Distance to neutral axis, c 264.15 mm
Width of the compression flange, b 104.4 mm
Thickness of the compression flange, t 13.2 mm
Area of the compression flange, Af=
b*t 1378.08 mm2
Minor axis radius of gyration, ry 43.8 mm
Mass per meter 82 kg/m
Second moment of area, Ixx 75780 cm4
ASME BTH-1 EQT 3-1 COMPACT SECTION
Check b/t< 0.38* (E/fy)0.5
b/t = 104.4/13.2 7.90909090
64

0.38* (E/FY)0.5
= 0.38*(2.00E5/355)0.5
9.28E+00
SINCE 7.90909 < 9.28 Ok
BENDING STRESS
ASME BTH-1 EQT 3-6 Allowable bending stress ,fb
fb = 1.1 *fy/f.s
fb =(1.1 * 335)/3 122.8333333 N/mm2
Bending moment, m
m = wl/4
m = (505215 *15000)/4 315759375 N/mm2
s= m*c/I
S = (1894556250 *
264.15)/75780*10000 1.16E+02 N/mm2
Check s = s < fb
116< 122.8333 ok
65

Table 4.3 Spreadsheet for Spreader bar two
ASME BTH-1 Weight, w 505215 N
MATERIAL
ASME BTH-1 SA- 36 MATERIAL
YIELD STRENGTH, fy 335 N/mm2
MODULUS OF ELASTICITY E 2.00E+05 N/mm2
DIMENSION UB 533x 210X 82xkg/m
UNIVERSAL BEAMS TO BS 4: PART1:1993
Length of the beam, l
9000 mm
Depth of the section, d
528.3 mm
Area of the compression flange, Af= b*t 1378.08 mm2
Mass per metre 82 kg/m
Check b/t< 0.38* (E/fy)0.5
b/t = 104.4/13.2 7.90909091
0.38* (E/FY)0.5
= 0.38*(2.00E5/355)0.5
9.28E+00
SINCE 7.90909 < 9.28 Ok
BENDING STRESS
ASME BTH-1 EQT 3-6 Allowable bending stress,fb
fb = 1.1 *fy/f.s
fb =(1.1 * 335)/3 122.833333 N/mm2
Bending moment, m
m = wl/4
m = (505215 *9000)/4 1136733750 N/mm2
s= m*c/I
S = (1136733750 * 264.15)/75780*10000 4.17E+01 N/mm2
Check s = s < fb
41.7< 122.8333 ok
Table 4.4 Spreadsheet for Spreader bar three
66

ASME BTH-1 Weight, w 505215 N
MATERIAL
ASME BTH-1 SA- 36 Material
Yield strength, fy 335 N/mm2
Modulus of elasticity E 2.00E+05 N/mm2
DIMENSION UB 533x 210X 82xkg/m
UNIVERSAL BEAMS TO BS 4: PART1:1993 Length of the beam, l 9000 mm
Depth of the section, d 528.3 mm
Area of the compression flange, Af= b*t 1378.08 mm2
Mass per metre 82 kg/m
Check b/t< 0.38* (E/fy)0.5
b/t = 104.4/13.2 7.909091
0.38* (E/FY)0.5
= 0.38*(2.00E5/355)0.5
9.28E+00
SINCE 7.90909 < 9.28 Ok
BENDING STRESS
ASME BTH-1 EQT 3-6 Allowable bending stress ,fb
fb = 1.1 *fy/f.s
fb =(1.1 * 335)/3 122.8333 N/mm2
Bending moment, m
m = wl/4
m = (505215 *9000)/4 1.14E+09 N/mm2
s= m*c/Ixx
S = (114e9 * 264.15)/75780*10000 4.17E+01 N/mm2
Check s = s < fb
4.17E1 < 122.8333 ok
Table 4.5 Spreadsheet for Shackle design for Spreader bar one
67

DESIGN AND CONSTRUCTION OF
LIFTING Maximum line load 505.215 KN
BEAM- AISC 2003
505215 TO TONNE 51.52 Tons
Safe working load 55 Tons
CROSBY GROUP CATALOGUE S- 2130
Nominal size 50.8 mm
Stock no 1019659
Weight 23.7002 KG
DIMENSION
A 10.4902 mm
B 71.12 mm
C 274.32 mm
D 68.834 mm
E 184.15 mm
F 144.526 mm
H 454.66 mm
L 323.85 mm
N 79.502 mm
TOLERANCE(+-)
C 6.25 mm
A 6.25 mm
68

Table 4.6 Spreadsheet for Shackle design for upper sling of Spreader two
BEAM- AISC 2003
Stock no 1019659
Weight 23.7002 KG
DIMENSION
A 10.4902 mm
B 71.12 mm
C 274.32 mm
D 68.834 mm
E 184.15 mm
F 144.526 mm
H 454.66 mm
L 323.85 mm
N 79.502 mm
TOLERANCE(+-)
C 6.25 mm
A 6.25 mm
69

Table 4.7 Spreadsheet for Shackle For Lower sling of Spreader bar two
BEAM- AISC 2003
Stock no 1019659
Weight 23.7002 KG
DIMENSION
A 10.4902 mm
B 71.12 mm
C 274.32 mm
D 68.834 mm
E 184.15 mm
F 144.526 mm
H 454.66 mm
L 323.85 mm
N 79.502 mm
TOLERANCE(+-)
C 6.25 mm
A 6.25 mm
70

Tabele 4.8 Spreadsheet for upper sling of Spreader bar two
LIFTING Maximum line load 505215 N
BEAM- AISC 2003
51520- TO TONNE 51.52 Tons
Maximum line angle 60 degrees
BETHLEHEM WIRE ROPE SLING LENGTH 6 m
GENERAL PURPOSE CATALOGUE .
ASME B30.5- 1995 IWRC(Purple or extra improved ploy (EIP Steel)
Structural steel to lift 505215 N
Sling class 19X7
Nominal strength 53.1 Tons
Rope diameter 29 mm
Approximate weight 3.422777 kg/m
DESCRIPTION
Strands 19
Wire per strand 7
71

Table 4.9 Spreadsheet for lower sling of Spreader bar two
BEAM- AISC 2003
Sling class 19X7
Rope diameter 29 mm
DESCRIPTION
Strands 19
Wire per strand 7
72

Table 4.10 Spreadsheet of Shackle design for upper sling of Spreader bar three
BEAM- AISC 2003
Stock no 1019659
Weight 23.7002 KG
DIMENSION
A 10.4902 mm
B 71.12 mm
C 274.32 mm
D 68.834 mm
E 184.15 mm
F 144.526 mm
H 454.66 mm
L 323.85 mm
N 79.502 mm
TOLERANCE(+-)
C 6.25 mm
A 6.25 mm
73

Table 4.11 Spreadsheet of Shackle design for lower sling of Spreader bar three
BEAM- AISC 2003
Stock no 1019659
Weight 23.7002 KG
DIMENSION
A 10.4902 mm
B 71.12 mm
C 274.32 mm
D 68.834 mm
E 184.15 mm
F 144.526 mm
H 454.66 mm
L 323.85 mm
N 79.502 mm
TOLERANCE(+-)
C 6.25 mm
A 6.25 mm
74

Table 4.12 Spreadsheet of uppersling for Spreaderbar three
REFERENCE CALCULATION OUTPUT UNIT
BEAM- AISC 2003
Sling class 19X7
Rope diameter 29 mm
DESCRIPTION
Strands 19
Wire per strand 7
75

Table 4.13 Spreadsheet of lowersling for Spreaderbar three
REFERENCE CALCULATION OUTPUT UNIT
BEAM- AISC 2003
Sling class 19X7
Rope diameter 29 mm
DESCRIPTION
Strands 19
Wire per strand 7
76

Table 4.14 Spreadsheet Design for the Padeyes for the Spreader bars
EN1991-1-
Table 3.1
Yield stress of pad eye, Fy = 335 N/mm2
Pin Hole Diameter, d1 = 80 mm
Cheek Plate Radius, r1 = 80 mm
Cheek Plate Thickness, T1 = 20 mm
Main Plate Radius, r2 = 180 mm
Main Plate Thickness, T2 = 55 mm
Sling Angle to the Horizontal = Ø 60 deg
Pin diameter is 5 mm less pin hole diameter,dp = 75 mm
Pad eye Code Check
Total thickness, Tt = 2*T1 + T2 = 95 mm
From AISC
9th ed, Sec.
B.5 Tab.B5.1,
Page 5-36
Minimum radius of the main plate is the Max. value between 1.25d1 or d1/2 + 3 100.00 mm
Adopt radius of Main plate r2 180 mm
Max. Module Weight = 51 mT
API RP 2A Factor of safety 2
Assume Structure is fairly evenly loaded about centerline
Sling Forces, R1 = 294.447 kN, R2 = 294.447 kN, R3 = 254.998kN.
From Sacs For a single sling lift, the tension in the sling is = 254.998kN kN
Analysis
Report
When the forces on the slings are resolved as shown in the sketch below
the loads are shared
R1 = 294.45 kN
R2 = 294.45 kN
R3 = 254.998kN kN
Maximum Sling Force, fs = 254.998 kN (25.499 Tonnes) 25.99 mT
Add 20% for any shift of CoG
Design Pad eye Force, Ps =1.2*P*10 311.88 kN
Bearing Stress Check
Actual bearing plate thickness, tb = (2T1+T2) 95 N/mm2
Area required, Areq = Ps / 0.9 fy = 1034.43 mm2
Thickness required, treq = Areq / dp = 13.79 mm
Actual thickness provided, tprov = 55 mm
thickness provided is ok
Actual bearing stress,fB = Ps/(dp(T2+2T1)) = 43.77 N/mm2
Allowable bearing stress = 0.9 fy = 301.50 N/mm2
301.5N/mm2
> 43.77N/mm2
Bearing Stress Check is ok
Tear-out - Shear Stress Check
Tear out shear area, fS = 4T1(r1/2-d1/2) + 2T2(r2 - d1/2) = 15400 N/mm2
77

Actual Shear Stress, fA = Ps / fS = 20.25 N/mm2
Allowable Shear Stress =0.4Fy = 134 N/mm2
134N/mm2
> 59.05N/mm2
Tear-out - Shear Stress Check
0.89 < 1 OK
Tensile Stress Check
Allowable stress on the net area of the pin hole for pin connected members,fT = 0.45fy = 150.75 N/mm2
Pin hole cross sectional area, pAs = T2(2r2-d1) + 2T1(2r1-d1) = 18600 mm2
5% impact factor sling vertical load component, 15.59 kN
sling vertical load component including 5% impact factor, Pvs 327.47 kN
Allowable tensile stress,fallow = fT x pAs = 2803.95 kN
sling vertical load component < Allowable tensile stress. Ok
R5k Actual tensile stress, factual = Pv / pAs = 17.61 N/mm2
Combined stress (Axial and Bending)
pad eye width, bw = 95 mm
Area of pad eye, Ap = T2 x bw = 5225 mm2
section modulus of the major axis, S1 = 1/6 T2bw
2
82729.17 mm3
section modulus of the minor axis, S2 = 1/6 T2
2
bw = 47895.83 mm3
pad eye axial stress, Pvs / Ap = 62.67 N/mm2
sling horizontal load component including 5% impact factor, Phs = 194.54 kN
center of hole to fixed edge, h1 = 47.50 mm
center of hole to centroid of lifting section distance, h2 = 0 mm
bending stress-major axis, Fbx = (Pvs x h2 - Phs x h1) = -192.94 N/mm2
In plane shear stress due to horizontal loading, fsh = Phs/T2bw = 37.23 N/mm2
5% impact factor sling vertical load component, Pn = Pside = 15.59 kN
minor axis bending stress,fbz1 = Pside x h1/S2 = 15.47 N/mm2
fbz2 = Pn h1/S2 = 15.47 N/mm2
Unity check for combined stresses, U = (fa + fbx + fbz2 + fbz1 / 0.6 fy) +(fsh/0.6fy)^2 <1 0.46
Cheek plate weld check
σcw = Ps * T1/(Tt*2r1* a) =
weld thickness, s 15 mm
throat of fillet weld, a = 0.7s = 10.50 mm
σcw = (Ps * T1)/(Tt*2r1* a) = 39.08 N/mm2
Unity Check (Bearing) 0.29
Stress on cheek plate weld,w = s x σcw = 410.37 N/mm
Design of shear strength of weld,Fvw.d =(Fu/(3)/(βw * γm2) =
Ultimate strength, Fu = 430 N/mm2
Correlation factor, βw = 0.85
L Partial factor of resistance of plate in bearing, γM2 = 1.25
Fww.d =(Fu/(3)/(βw * γm2) = 134.90 N/mm2
Design strength of weld per unit length, Fw,RD = Fvw.d * a = 1416.47 N/mm
Unity ratio 0.29
78

WELD OF PLATES TO PADEYE MAIN PLATE
Load on weld assume weld takes all load,Lw = 450 kN
minimum weld of padeye plate, with resistance factor Tweld , Lw/(L x Fsw) =
Fsw = 150.75
L = 1450 mm
minimum weld of padeye plate, Tweld , Lw/(L x Fsw) = 2.06 mm
provide weld size 12 mm
Vonmisses stress check (as per WSD)
tensile stress, factual
bearing stress, fB
In plane shear stress due to horizontal loading, fsh
5% impact factor sling vertical load component, Pn =
vonmisses stress at edge of web,fm = [(factual+ fB(fsh))2
+3 x pn
2
)0.5
61.13 N/mm2
Allowable stress ( Vonmisses) = 0.75fy = 251.25 N/mm2
251.25N/mm2
> 61.13N/mm2
vonmisses check is ok
79

Table 4.15: Showing member sizes for seafastening design.
P19 6.1 19.1 2572.45
P25 12.2 25.4 6793.84
P31 3.05 31.8 2110.99
P44 3.05 44.4 2905.45
P50 9.15 50.8 9899.58
P44 6.1 44.4 5810.91
P31 6.1 31.8 4221.99
P19 16.8 19.1 7084.78
Total = 62.55 Total = 41399.99
`
80

Table 4.17 Member Joint Description (sea fastening)
The member joints description are summarized in the table below
Table 4.18 Tubular Member Properties (sea fastening)
81

Table 4.19 Forces and Moment (sea fastening)
Table 4.20 Member Stress Report at Maximum Unity Check(sea fastening)
82

Table 4.21: Codes and Standards
API RP 2A-WSD
American Petroleum Institute-Recommended Practice
for planning, Designing and Construction of Fixed
Offshore platforms-Working Stress Design
AWS D1.1/D1.1M
American welding Society-Structural Steel Welding
Code
AISC ASD
Manual of Steel Construction-Allowable Stress
Design, 9th
Ed AISC
API Spec 2B
Specification for the fabrication of Structural Steel
Pipe
ASTM
American Society of Testing Materials -various steel
material specification
TABLE 4.22 Weight computation of Caisson for installation onto the FPSO.
SLG 5 Dummy
P19 6.1 19.1 2572.45
P25 12.2 25.4 6793.84
P31 3.05 31.8 2110.99
P44 3.05 44.4 2905.45
P50 9.15 50.8 9899.58
P44 6.1 44.4 5810.91
P31 6.1 31.8 4221.99
P19 16.8 19.1 7084.78
Total = 62.55 Total = 41399.99
Table 4.24 Element Stress Report(30°l
lift)
84

Table 4.25 Member forces and moment(30°l
lift)
85

Table 4.26 Joint Deflections and Rotations(30°l
lift)
87

Table 4.27 Joint Deflections and Rotations (60°l
lift)
88

Table 4.28 Member forces and moments(60°l
lift)
89

Table 4.29 Element Stress Report(60°l
lift)
90

Table 4.30 Element Stress Report. (90°l
lift)
Table 4.31 Member forces and moment
ANGLE MAX MEMBER FORCE(KN) MAX MEMBER MOMENT(KN.m)
300
111.73 1775.67
600
225 1247.80
900
1430 0.00
Table 4.32 Joint deflections and rotation.
ANGLE MAX JOINT DEFLECTION(CM) MAX JOINT ROTATION(RADIANS)
300
13.856 0.00704
91

600
6.98 0.0084 5
900
0.00 0.00
Table 4.33 Element stress (unity check).
ANGLE MAX SLING UNITY CHECK MAX MEMBER UNITY
CHECK
300
0.685 0.47
600
0.578 0.37
900
0.578 0.37
Table 4.34 Deflection for 30 degree lift
92

Table 4.35 Deflection for 60 degree lift
JOINT LENGTH(MM) DEFLECTION(CM)
P0 0 0
P8 16.8 -4.229
P9 22.9 -5.888
93
Node LENGTH(MM) DEFLECTION(CM)
P0 0 0
P8 16.8 -9.61
P9 22.9 -12.55
P10 29 -13.85
P11 38.15 -12.82
P12 41.2 -11.74
P13 44.25 -10.275
P14 56.45 -2.149
P15 62.55 0
P16(SLING) 67.55 -13.856

DESIGN OF A MODEL HAULAGE TECHNIQUE FOR WATER FLOODING CAISSON ASSEMBLY.

DESIGN OF A MODEL HAULAGE TECHNIQUE FOR WATER FLOODING CAISSON ASSEMBLY.

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