Standard scope of activities - Strukton Immersion Projects

Standard scope of activities

Although each project has its own dynamics and scope, a genuine scope of works for Strukton Immersion Projects is starting with the Design Basis for the floatation, transport and immersion, followed by the detailed temporary works design, engineering and preparations. All engineering and preparation come together in the final performence of floatation, transport and immersion of elements by Strukton Immersion Projects.

Phase 0: Design Basis

  • Producing design report with and all constrains and assumptions
  • Basic design transport and immersion systems
  • determination of the general floatation, transport and immersion process
  • Weather window analyses
  • Planning OTAO® activities
  • General OTAO® drawings

 

Phase 1: Detailed temporary works design and engineering

  • Determining loads involved in transport and immersion
  • Processing salt/fresh water quality data
  • Design of temporary bearings (tiles and pins)
  • Dimensioning and detailed specification of transport and immersion
  • Prestress Dimensioning of ballast tanks
  • Detailed design of OTAO® suspension points
  • Detailed design deck layout
  • Detailed transport and immersion loads
  • Detailed design mooring system
  • Detailed design winch system in construction dock
  • Detailed design winch system for immersion
  • Detailed design of closure joint panels
  • Recommendation on choice of 'Gina' gasket profile
  • Dimensioning closure joint wedges
  • Dimensioning bulkheads
  • Dimensioning underflow system
  • Processing of as-built dimensional data
  • Dimensioning of the Jacking System for horizontal positioning
  • Outline dimensional characteristics during immersion

 

Phase 2: Preparations

  • Detailed method statements and checklists
  • OTAO® coordination during casting of tunnel elements
  • Step by step drawings for immersion
  • temporary foundation tiles placement
  • Preparation tunnel elements for immersion
  • Dredging immersion trench (third parties)
  • Preparation immersion trench (third parties)

 

Phase 3: Work at construction dock including floataion and temporary mooring

  • Floating and warping TE
  • Warping out TE
  • Transporting TE to temporary mooring site
  • Preparing temporary mooring site
  • Preparing TE for immersion
  • Installing access shaft and survey tower
  • Filling ballast tanks and checking for leaks
  • Emptying TE ballast tanks
  • Installing winches on anchors and working platforms developed by us and made available
  • Preparing immersion pontoons
  • Securing immersion pontoons to TE
  • Placing fenders on TE
  • Checking navigation depth of access channel for keel clearance
  • Attaching winch wires to TE by divers and riggers

 

Phase 4: Works at the immersion location includiong transport and temporary foundation

  • Setting out anchors and installing winch pontoons
  • Installing anchor points on shore for anchoring
  • Transporting TE to immersion site
  • Making immersion trench ready (survey/anchor points etc.)
  • Installing anchors
  • Installing winches
  • Attaching winch wires to TE by riggers
  • Securing TE in winch wires
  • Seeking sheltered site in fast current conditions
  • Attaching forward lines
  • Miscellaneous diving work
  • Loading TE with ballast to immersion weight
  • Immersing TE
  • Dimensioning during immersion
  • Diver check of 'Gina' gasket
  • Positioning of jacks on foundation tiles, check by divers
  • Attaching horizontal pulling cylinders (by divers)
  • Fastening TE
  • Emptying immersion joint
  • Check of TE position
  • Jack corrections of TE position
  • Check of immersion trench
  • Under flowing TE
  • Check measurements of under flowing reaction forces
  • Removing towers and jacks 
  • Backfilling and covering immersion trench 
  • Diving work for the immersion operation

 

Temporary provisions

  • Deck layout
  • Modular Steel Bulkheads 
  • Bulkhead doors
  • Ballast water system
  • Remote controlled immersion systems
  • Pontoons
  • Winches, wires and shackles
  • Access shafts
  • Survey towers
  • Tugs
  • Sheer legs and pontoons
  • Sandflow
  • Support vessels
  • Jacks