Seismic Response of Bucket Foundations for Offshore Wind Tower

Abstract

This study aims to investigate seismic response of bucket foundations for the support of offshore wind tower. The prototype design of the bucket foundation was scaled down with a scaling number of 1/240 to manufacture the model. An additional gravity base foundation (GBF) model was prepared and its diameter is same with the bucket. The dynamic centrifuge tests for both models installed in sandy soil were carried out at 60 G resulting in the 1/4 scale prototype. Two real earthquake motions, Kobe and El Centro earthquakes were applied to the models. The earthquake motion scaled with peak accelerations from 0.02 G to 0.2 G was excited at the base of the soil container. The acceleration at the platform level (i.e. the connection of the tower and foundation) for the bucket foundation is lower than that of the GBF. The types of earthquake affected the responses at the platform. The displacement at the platform level of the bucket was also lower than the GBF. The contact pressure was at the bottom invert of both models and skirt surface of the bucket. The contact pressure at the bottom invert of the GBF significantly increases with increasing excitation while that of the bucket is negligible. The contact pressure at the skirt surface of the bucket significantly increases due to seismic loading.