Observations on bucket foundations under cyclic loading in dense saturated sand

Offshore wind farms will play a significant role in the European energy supply of the coming years. Today, one of the main challenges faced by the offshore wind market is to reduce the cost of turbine foundations. The monopod bucket foundation is a possible solution to this problem. The long-term cyclic response of this foundation is not fully understood. In this article, a single gravity physical model is described, an experimental campaign is presented and the observed results are discussed. The aim of the study is to explore the general pattern of response of the foundation under cyclic loading. The bucket is installed in water-saturated dense sand. The experimental rig induces cyclic loading to the foundation in terms of overturning moment and horizontal loading. A number of cyclic loading tests is presented. The loading features (i.e. amplitude and average of the cycles) differ for each test. The discus¬sion of the results focuses on three aspects: a critical cyclic loading configuration isfound and compared with a previous study, a limit value of cyclic moment for which no degenerative rotation occurs is obtained and the effect of the loading frequency on the plastic displacement is explored.