The nonlinear Beam-on-Winkler Foundation model was developed based on shaking table test

utilizing the two-step method

equivalent single pile method and Nonlinear Beam-on-Winkle-Foundation method. The effect of soil-pile interaction was considered in this model. First

the pile group foundation was simplified to an equivalent single pile according to stiffness equivalence theory. Secondly

soil-pile interaction was modeled by macroelement which was composed of paralleled spring and damper components. Thirdly

the soil displacement and pore water pressure ratio of free field under seismic load were calculated. Finally

the displacement of the free field and the pore pressure ratio during the earthquake were conducted as the boundary condition of nonlinear Beam-on-Winkle-Foundation. This simplified method was implemented in the FE software and verified by the results obtained from the shaking table tests.