Kinematic response of large diameter floating pipe piles under vertical S-wave loading

This paper investigates the seismic response of a large diameter floating pipe pile subjected to vertically propagating S-waves. Its kinematic response is analytically derived using a rigorous continuum elastodynamic model. The model simulates the soil between the pile toe and bedrock as a fictitious soil pile, and the governing equations for the soil, pile, and virtual pile are derived accordingly. The total wave field is decomposed into scattered and free wave fields, and the influence of scattered waves on the pile-soil system is accounted for through separation of variables. The developed solution can be reduced to the solid floating pile case, and its accuracy is validated by comparing its predictions with the results of available results for solid floating piles. In addition, the comparison of the present results with the analytical solution of end-bearing piles and floating pipe piles in the numerical results reveals that the general trends are similar. The effects of pile slenderness ratio, pile-soil modulus ratio, and pile diameter ratio on the dynamic response of pipe piles are systematically analyzed. The results indicate that there is a significant difference between the seismic performance of pipe piles and solid piles. In addition, the seismic pile response is evaluated in the time domain under realistic seismic wave excitation to demonstrate the applicability of the solution for practical engineering problems.