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17/10/2013 2
T&I of Offshore Structures
Staalbouwdag 2013 – Offshore Seminar
Seaway Heavy Lifting – Installation Contractor’s Perspective
Offshore…?
Transportation – Steel design and fabrication
Installation – Steel design and fabrication
SHL installation equipment
2,500 Mt revolving capacity
Length 183 m / Breadth 36 m / 140 pob
2,500 m2 deck space
5.5 m minimum draught
Anchors
5,000 Mt revolving capacity
Length 183 m / Breadth 47 m / 220 pob
4,000 m2 deck space
8.5 m minimum draught
Anchors and DP 3
Stanislav Yudin Oleg Strashnov
4
17/10/2013 5
Transportation
Fabrication
Shipbuilding vs Structural Design
Steel quality
Loadings
Motions
Wind
Barge deflections ?
Fatigue
Design considerations
Load out methods
Barge layout
Barge strength
Barge furniture
SAFETY (safe access)
Lifted Loadout
Use of (multiple) floating or mobile cranes
Set-down on cargo barge
Grillage design ‘simple’
17/10/2013 10
Trailered Loadout
17/10/2013 11
Use of multiple trailer lines
Barge strength
Barge ballasting
Tidal restrictions during operation
Grillage design with lots of constraints
Cargo barge
October 2013
Qatar - Barzan Field
Structures fabricated in Korea (Hyundai)
All topsides ~3000t
Being installed by HLV Oleg Strashnov
17/10/2013 12
Cargo barge
Delivery of structures by the fabricator (seafastened)
Barge furniture re-instated as per Class en Installation Contractor requirements
Barge prepared by fabricator for sail away; acceptance by MWS and Installation Contractor
Barge cleaned of loose items
Ballasted and tanks closed
Safe access to the barge (ladders) and seafastening (scaffolding) provided including handrailing
17/10/2013 15
Seafastening removal
Moving barge
Working at height
“Dark and wet”
Limited work space
Back-up plan if this doesn’t work
It is easy to design this type of seafastening…….
It is very cumbersome to work with it offshore and causes safety issues!!!
17/10/2013 20
Seafastening removed
Routing of hoses
Design of jacket systems
Outfitting on yard
Only small fabrication but can have a large impact on the successful completion of the project……
17/10/2013 23
Transportation Analysis
Wind energy sector
New designs
“New” installation methods
Discussions:-
- Barge strength
- Barge class requirements
- Transportation seastate
- Analysis methods (everything in one model)
17/10/2013 24
Transportation Analysis
FEM analysis of barge, grillage and structure
Load cases for barge deflections (hogging, sagging), weight variations and internal tank pressures
Load cases for design seastates
17/10/2013 25
17/10/2013 26
Installation
Fabrication
Lifting Appliance certification
Steel quality
Welding procedures
Loadings:
Dynamics
Weight contingencies
Load distribution
Design considerations
Lifting height (clearance to crane)
Interference with equipment
SAFETY (safe access)
17/10/2013 28
Spreader Frame
Weight of frame (100 – 200 t)
Weight of rigging on top (3% of lift weight)
Supported during transportation
Safe access to personnel on top
Protection of equipment during lifting and removal of rigging system
Removal of support structure (in between equipment….)
17/10/2013 29
Spreader Frame
Designed as lifting appliance (Lloyds, DNV, GL)
Certification requirements:-
Design appraisal
Material certification and traceability
Welding procedures (qualification)
Test loading…..?
Designed for single use?
17/10/2013 41
T&I - Trends
From practical approach to scientific approach
What is design safety
What is failure
Academic “solutions”
“Guidelines” are “Rules”
Safety is to be a key driver for the design of permanent and temporary structures
More advanced design and calculation tools
FEM
Simulation
Use of high strength steel
Fy 460-690 N/mm2
Lifting appliances
Seafastening
Use of fibre rope technology
Lifting slings