Life cycle displacement of suction foundations for offshore wind turbines

Offentlig prosjektsammendrag

The project develops and optimises calculation procedures for estimating the long term deformations of foundations supporting offshore wind turbines. Offshore wind turbine Foundations must resist the environmental loading (wind, wave, current etc.) passed from the turbine structure. To ensure the normal operation of the turbine, there are strict serviceability requirements on the allowable deformation on the foundations (e.g. tilt). Over the design life of the wind turbines, the foundations are subjected to millions of load cycles. Due to repeated loading, the deformation accumulates and could jeopardise the operation of the turbine if not designed properly. However, due to the complexity of the environmental loading on the foundation over the life cycle of the turbine, the evolution of soil behaviour under cyclic loading and complicated processes such as consolidation, predicting the long term deformation for offshore wind turbine foundations is a challenging task. As of today, this is often dealt in a simplified (perhaps conservative) way, which could have significant implications for the safety and economics of these wind turbine structures. This project develops an improved procedure for calculating the long term deformation of offshore wind turbine foundations. This requires a detailed study into the loading characteristics on the wind turbine foundation and a streamlined procedure to calculate the deformation using soil models that can account for complex cyclic loading on the soil.