Effects of rocking impedance and soil shear stress of the free-field on the dynamic response of an end-bearing pile during horizontal earthquakes

An increasing number of pile foundation with large diameter are utilized in civil and offshore engineering in areas of active seismicity. This paper focuses on studying the effects of rocking impedance and soil shear stress of the free-field on the horizontal seismic responses of pile foundation. A substructure model in frequency domain is utilized to simulate pile-soil dynamic interaction during horizontal earthquakes. The soil is considered as viscoelastic media and the pile considered as one-dimensional (1D) rod modelled by Timoshenko beam theory. First, the analytical expressions of the horizontal and rocking impedances for an end-bearing pile are obtained. Further, the earthquake input method for 1D finite element analysis of pile-soil interaction on rigid bedrock during horizontal earthquakes are developed, where the soil shear stress of the free-field is considered. Finally, the proposed model is used to investigate the effects of rocking impedance and soil shear stress of the free-field on the seismic response of the pile with different soil and pile parameters.