Numerical modeling for the response of bucket foundation under long-term cyclic loading

Abstract

Estimation of accumulated lateral displacement and settlement are critical in design of wind turbine foundation. However, there have been few studies exploring the response of bucket foundation to long-term cyclic loading. We perform a series of three-dimensional finite element analyses of bucket foundations installed in sands and clays. An empirical formulation which captures the stiffness degradation observed in cyclic triaxial and simple shear tests is implemented into the finite element analysis in the form of a user subroutine. It is shown that the cyclically accumulated rotation of the bucket foundation increases with the number of cycles and cyclic amplitude. In particular, the magnitude of the moment and the position of the horizontal load are shown to significantly influence the cyclic response. Extensive numerical simulations are required to develop design charts for predicting the accumulated deformation of bucket foundation under long-term cyclic loading.