Introduction BAM and Van Oord have teamed up to Design, Manufacture and install reinforced concrete gravity base foundations (GBFs) for the offshore wind industry. The concept for the GBF has been developed from BAM and Van Oord s wide experience of designing and constructing immersed tube tunnels and gravity base structures. 2
Experience 3
Experience 4
FLOW research program, demonstration project FLOW = Far and Large Offshore Wind Innovation programme for Dutch wind industry Aims to accelerate development and reduce costs and risks BAM, Van Oord and Deltares are partners in FLOW. Project for demonstration of GBF underway. 5
Gravity Base Foundation Waterdepth 30-60 m Larger windturbines 5,6,7 MW Round 3 metocean conditions Steel shaft, Diameter: 5.5 7.0 m Concrete caisson Diameter: 30 m Self buoyant Draft < 10m Sand ballasted 6
Gravity Base Foundation, hybrid construction Optimal use of materials Low weight Low centre of gravity Shorter construction time Lower loads Uncomplicated connection of secondary steel Less joints Corrosion protection as monopile 7
GBF design: structural calculations DNV-OS-J101 Design of Offshore Wind Turbine Structures [10] GL Wind 2005 [8] Appendix 4.H Estimation for design wave loads for Rigidly positioned structures Hydrodynamic loads (Goda, Morrison + ComFLOW) Geotechnical stability (Plaxis, Dcycle) Structural calculations; extreme stresses, fatigue. Finite Element Method (SCIA) 8
Simulation to predict environmental loads: ComFLOW 9
GBF design: geotechnical interface 10
Design verification Physical model testing DNV Verification of (static) floating stability Static and dynamic characteristics (roll, heave and sway) Response to waves during transport and installation Touchdown behaviour Scour testing (planned) Verification of Basis of Design Optimized and cost effective design. 11
Fabrication: optimised for industrial production 12
National contractor with local presence BAM Nuttall, close to the local area. Close to customers, local planning and environmental authorities and the local supply chain. Directly employed workforce in the local area: Constructing the yard brings an estimated 200 jobs Producing GBF s brings an estimated 400 jobs Additional jobs for local suppliers 13
Marine works Van Oord has a large state of the art fleet and the experience to perform the necessary marine works. Use standard towing vessels for installation. Only limited weather window for installation necessary. 14
Eco design No piling, no noise Aquaculture opportunities Artificial reef development 15
Advantages of our solution Cost effective solution Standardised design, adaptable to local conditions Hybrid construction: concrete caisson, steel shaft Fully self buoyant, no expensive jack-up or heavy lift vessels Durable, re-powerable Low Risk Reliable, experienced partner Robust and practical solutions Well developed supply chain Low risk marine operations Local presence, in house knowledge and capability And: local content, made in UK 16
Reliable, Robust, Ready