Gravity Tripod Foundation Put through Paces

Hydraulic engineering and offshore renewable energy specialist HR Wallingford is conducting physical model testing for a new offshore wind foundation known as the Gravity Tripod.

The company is working with Offshore Design Engineering (ODE), DNV-GL, Cambridge University and the Offshore Renewable Energy (ORE) Catapult to test and certify the new offshore wind foundation concept designed by Offshore Wind Logistics and Construction (OWLC). The project is funded by the UK’s Department for Business, Energy and Industrial Strategy (BEIS).

Matt Bleasdale, Director of OWLC, said: “The Gravity Tripod is a unique structure combining the best aspects of other foundation concepts into one low cost solution. It requires no piling, is low drag, low scour, and installed with minimal seabed intervention. The structure is able to accommodate turbines from 3 to 16 MWs, and, having been designed for low bearing pressures, is capable of accommodating a wider range of seabed types, with less seabed preparation, than other gravity base designs.”

The Gravity Tripod foundation project will go through a series of stages, with certification from DNV, in preparation for demonstration of the design with a prototype structure.

Design work and optimisation will be undertaken by ODE, with testing of the physical components conducted by ORE Catapult. Cambridge University will conduct geotechnical sediment modelling, looking at the interaction between the structure and sea bed.

HR Wallingford will conduct physical model testing to investigate the loads applied to the structure during installation, those caused by exposure to large waves once the foundation is in place, and to determine the amount of erosion (scour) that may develop around the base of the structure if left unprotected.

Dr David Todd, Business Development Manager for Research at HR Wallingford, said: “The foundation will be subjected to rigorous physical testing in the Fast Flow Facility, a unique wave-current-sediment flume designed for the offshore wind market, making it the ideal location for installation, survival and scour testing of offshore wind foundations.”