Study on Damage Mechanism for Foundation Pile of Girder Bridge under Seismic Influence

Based on the analysis for seismic load and failure modes of pile foundation, this article adopts dynamic Winkler foundation beam model, and employs continuous distributional and independent spring and damper, instead of the dynamic resistance of the soil around the pile, and to explore interaction between pile and soil dynamic at horizontal load. In consideration of six kinds of boundary conditions combination, this paper proposes the solution method for displacement and internal force on pile. From analysis of cases, it finds that the effect of pile's length on dynamic response can be negligible when pile slenderness ratio l/d>20, and the pile can be simplified into infinite long pile. Dynamic response of pile increases with the increase of stiffness ratio. When establish the control equations, influence of axial force can not be ignore. Otherwise, results will be small than the actual value.