Predicting monopile behaviour for the Gode Wind offshore wind farm

摘要

Monopiles used as foundations for offshore wind turbines often have very large diameters and low length to diameter (L/D) ratios. Their response to lateral and moment loading is often modelled based on the API p-y method, although this was developed for slender piles with relatively small diameters. Theoretical studies and field monitoring have shown that this method may not accurately describe monopile behaviour, in particular the lateral load-displacement response for serviceability conditions. This paper presents advanced 3D Finite Element (FE) analyses undertaken during design of the Gode Wind offshore wind farm at a sand dominated site in the German North Sea. Two turbine locations with different soil profiles and varying monopile L/D ratios were analysed to compare the load-displacement and moment-rotation curves with the API p-y method. The FE analyses predict a stiffer response of the monopile from initial loading until the design ULS condition, which is consistent with field experience.