Lecture 10

Fabrication & Load-out

Lecture Objectives

To provide understanding of onshore
fabrication & load out.
o Description and methods concerning
offshore structures fabrication & load out.
o Fabrication of offshore structures and load
out activities.
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 Lecture Outline
1. Overview on Onshore Fabrication
2. Fabrication Phases
3. Overview on Load-Out
4. Load-out methods
5. Design Criteria for Load-Out
6. Load-Out Activities
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Onshore Fabrication
WHY onshore fabrication?
Offshore difficulty due to :

Environment

Cost

Schedule

Safety
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 Onshore Fabrication
A place where onshore fabrication activities takes
place is called Fabrication Yard.
Onshore Fabricators identified by PETRONAS in
Malaysia are:
1. MMHE : Malaysia Marine Heavy Engineering Sdn. Bhd.
2. RFSB : Ramunia Fabricator Sdn. Bhd.
3. KHLE : Sapura Kencana HL Engineering Sdn. Bhd.
4. THSB : Tabung Haji Sdn. Bhd.
5. SDE : Sime Darby Engineering Sdn. Bhd.
6. BDEWC : Brooke Dockyard & Engineering Works Corp.
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Onshore Fabrication
Fabrication
Philosophy
Jacket destined Jacket destined
for shallow for deeper
water < 30m water > 30m
• Usually erected • Usually erected on
vertical, i.e. in the it’s side
same position
(vertical) as the final •Such jackets are
installation loaded by skidding
out onto a barge
•Such jackets may be
lifted or skidded onto
the barge.
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 Onshore Fabrication
HOW to reduce cost and time for onshore
fabrication?
1. Subdivision into components and modules.
2. Concurrent fabrication of major components.
3. Planning the flow of components to their assembly
site.
4. Simplification of configurations and standardisation
of details, grades and sizes.
5. Selection of structural systems that utilize skills and
trades on a relatively continuous and uniform basis.
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Fabrication Phases
1 Engineering (fabrication)
2 Procurement
3 Shop-Fabrication
4 Assembly
5 Erection
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 Fabrication Phases
Target Level 1 Oct Nov dec Jan Feb mar Apr May Jun Jul Aug Sep Oct Nov
Engineering 55% E E E E E E E E E C Construction
Procurement 32% P P P P P P P P P P T Transport
separators (UAE) E E P P P P P P C C C I Installation
Power gen E E P P P P P S C C C E Engineering
Hydrocyclone E E P P P P P S C C C P Procurement
Jacking sys (Europe) E P P P P P P S C C C S Shipping
Legs (Europe) E P P P P P P P P P T T T T
Metering (UAE) E E P P P P P P C C C
Valves/Pumps/Winches E E P P P P P S C C C
Crane E E P P P P P P P C C
heat exchangers E E P P P P P P P C C
Flowlines (Europe) E E E E P P P P P P P T T T I
Turret E E P P P P S C C C C T T T I
FAB MOPU 11% C C C C C C
Integration topsides C C C
FAB FSO 11% E E E C C C C C C C C T T T
Transport MOPU//FSO T T T
Installation HUC I I I
Start Up > <
Shop Fabrication
CS2-1(L2)12:
Aerial view of fabshop for assembly of cellar deck plate girder Load out 10
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 Shop Drawing : Main
CS2-1(L2)12: Fabrication 11
& Load Out
Shop Drawings : Components
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 Cutting Plan
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Fabrication Phase

Assembly
Row 7
Row 3.0
Row 3.1
Assembly of Cellar Deck
frame Row 3.1 to 7.0
CS2-1(L2)12: Load out 14
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Fabrication Sequence :Topsides
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Deck Fabrication
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 Fabrication Sequence :Jacket
CS2-1(L2)12: Load out 17
Fabrication Phase

Erection
Lifting of X-panels for Row B between elev. -14K & -
34K
CS2-1(L2)12: LoadLoad
CS2-1(L2)12: out out 18
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 Jacket Fabrication
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Overview of Load-Out
Move the completed
structure onto the
transportation barge
which will transport
it offshore
Cranes
Barge Skid beam
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 Load-out Methods
1 2 3
Skidding Transporter Lifting
(Bogie /
SPMT /
Trailer)
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Load-Out Method

Skidding
1. Feasible for items of any weight.
2. The system consists of a series of steel beams.
3. Each skid is provided with a hydraulic jack to
control the reaction.
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 Load-Out Method
Arrangement of Equipment for Skidded Load-out
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Load-Out Method

Transporter (Bogie)
1. Specialized trailer units
that is combined to act
as one unit
2. The load capacity over
the projected ground
area varies from
approximately 55 to 85
kN/sq.m.
3. The units can drive in all
directions and negotiate
curves.
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 Bogies / Trailers
•SPMT (Self
Propelled
Modular
Transporters)
•Trailers
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Load-Out Method
Lifting

Dedicated for small structures built on the quay.
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 Design Criteria for Load-Out
Structural Component ( Load-out by lifting)
Lifting Point
Hook Point
SLINGS 1)Shackles
MAIN BEAMS
LIFTING
POINT
2)Padeyes
COG
MAIN 3)Trunnions
TRUSSES
FINAL
END FRAMES SUPPORT
POINTS
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Design Criteria for Load-Out
1. Lifting attachments (i.e.
padeyes, padears &
trunnions) should be
designed to allow
installation.
2. Lifting attachments
may be oriented, when
the final weight has
been determined and
the location of Center
of Gravity(COG) is
established.
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 Design Criteria for Load-Out
3. Design Basis for Slings.
- Slings shall be sized such that
the Safe Working Load (SWL) SLINGS
of the sling is in excess of the
sling loads evaluated on the 40%
basis of the factored lift
weight, with the pre-defined 60%
slings load distribution.
- No additional impact factor
shall be used
- For 4 slings to a common block
a 60% - 40% load distribution
in diagonal slings shall be 29
assumed.
Design Criteria for Load-Out
• Substructure (i.e. Jacket) Load-Out
1. 3-dimensional computer analysis shall be performed
to check the jacket structure for loads imposed
during load-out
2. Loads arising from all rigging equipment for
installation that will be yard-installed must be
considered in the load-out analysis.
3. In order to account for any unevenness of railtracks
and skid beams or inaccurate barge lineup, the
analysis shall assume a 3 point support condition in
addition to the basic 4 point support condition.
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 Design Criteria for Load-Out
• Superstructure/Topsides Load Out
1. Strength of all joints and members shall be checked
for load-out conditions.
2. The deck or module to be skidded shall be analyzed
by considering;
• 3/4 legs are active
• 4/6 legs are active
•6/8 legs are active
3. Loads arising from all rigging equipment for
installation that will be yard-installed must be
considered in the load-out analysis.
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Design Criteria for Load-Out

Allowable stresses
1. The maximum stresses during load-out shall not
exceed the basic AISC allowable stress levels
unless otherwise approved by the Company.
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 Loadout Checklist : CSP-04
- Prior to load-out, there are few of items that
need to be checked. Those items are;
 Structural Shop & As Built Drawings
 Compliances of Structural Drawings & Fabrication
Drawing to PTS 20.097 addendum item 9
 Load-Out Procedure
 Weighing Procedure
 Ballasting Calculations
 Design/Field Modification/Red-Line Marking
Incorporation and Status
 STQ Status
 Extent of Carry Over Works Offshore
 Outstanding Structural Work
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Loadout Procedure
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Ballasting Calculations
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Ballasting Calculations
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 RO-RO Ramp and Wedge
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Major Load-Out
1. 24 cranes were involved in the
two major side frame lifts
(Platform Cerveza,300m long).
2. Bullwinkle jacket, one of the
world's largest, -
-Fabricated in Japan,
-Transported by barge to Texas
-Assembled by jacking towers
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 End
CS2 Structural Design Offshore
(Level 2) – Lecture 10
Fabrication & Load-Out
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