Not only is the suction bucket foundation subjected to vertical loading induced by weights of offshore platform and equipments

but also undergoes horizontal force and moment caused by winds and waves. Therefore the performance of bucket foundation subject to the joint loading of both vertical force (V) and horizontal force (H) is one of the key issues in design and construction of a bucket foundation. A 3-D FEM-based computational model of bearing capacity and failure mechanism of bucket foundation under the above joint loads is proposed and then numerically implemented using the general-purpose finite element analysis package ABAQUS. The normalized relationship between the factor of ultimate bearing capacity and resulting displacement is obtained by applying the displacement controlled method for homogeneous soft soil profile. The failure envelope of the foundation in the load subspace of vertical and horizontal forces (V-H) is determined by utilizing loading procedure of the Swipe test. The load-carrying performance and failure mechanism of bucket foundation under joint loading are interpreted from the standpoint of upper-bound limit analysis based on the deformation pattern obtained from numerical analyses. The numerical results computed using the proposed method is helpful to engineering practices.