Importance of the soil–structure interaction in the optimisation of the jacket designs of offshore wind turbines

Abstract

Advances in the design process and understanding of the structural behaviour of jacket-type foundations for offshore wind turbines are fundamental to the expansion of these devices in medium-depth waters. The structural evaluation of jacket foundations is a complex and computationally expensive task because of the large number of structural elements and numerous load scenarios and requirements imposed by international standards. In this context, the soil–structure interaction is not usually incorporated into the optimisation process of these devices, assuming that the foundation flexibility does not significantly affect the supporting structure. This study investigated an approach for analysing the influence of the soil–structure interaction on the structural design. To perform a relevant analysis, an optimisation process was used to obtain feasible designs for a 10-MW wind turbine in a specific location. To optimise and evaluate the jackets, a structural model based on static equivalent analysis of the most representative load scenarios for environmental loads was used. The obtained designs highlight the importance of considering the soil–structure interaction for evaluating the technical requirements imposed on these structures, especially in the ultimate limit states.