With this type of foundation, a conical joint is to be used at the top of the London Array monopiles to prevent transition piece slippage. Nearly 100 have been installed already.
Work on the new design was prompted by some problems previously reported in other monopile foundations. As well as addressing foundation grouting and slippage problems, the new design takes into account variation in water depths and moveable seabed conditions across a wind-farm site.
The 630MW, 17-turbine first phase of London Array, in the outer Thames Estuary in south-east England, is due for completion at the end of this year. It is being developed by a consortium of Dong Energy, E.on and Masdar.