Behavior of Bucket Foundations for Offshore Wind Turbines under Cyclic Horizontal Loading

Bucket foundation designed for offshore wind turbines is subjected cyclic horizontal loads and moments due to wind, wave and current. A three dimensional bucket-soil numerical model was developed to investigate the behavior of bucket foundation under cyclic horizontal loading in sand by explicit dynamic Solver, numerically implemented in the framework of the general-purpose FEM software package ABAQUS considering the degradation stiffness model determined in cyclic triaxial tests. The effects of the number of loading cycles, bucket length, diameter and the loading state on the accumulation rate of lateral deformation are analyzed. The relation of displacement accumulation under cyclic and static loading is obtained. Using the result of displacement accumulation the foundation stability can be checked.