A 2D finite element model of soil-pile-frame structure nonlinear interaction was developed using finite element software ABAQUS.Damaged plasticity model and dynamic visco-plastic memorial nested yield surface model were adopted to model concrete and soil respectively.Beam element and rebar element were used to model RC piles and inner longitudinal rebars.A surface-based contact pairs method was used to simulate the interaction effect between soil and piles.The numerical models of free field

frame structure and soil-pile-frame structure were validated by comparing its analytical predictions with other well verified software results.It is concluded that the nonlinear response of soil close to pile cap is very large

while the soil between pile groups has a small nonlinear response and moves with pile groups together to a great extent. The acceleration response of pile cap may be larger than that of the superstructure because of soil-pile interaction effect.In addition

the acceleration histories of the pile cap show obvious spikes.With increase of seismic intensity

the acceleration response spectra show a tendency of degeneration from multiple peaks to single peak which reveals characteristic of single degree-of-freedom system.