Study on Dynamic Behavior of Abutment of Urban Bridge in Considering of Footing Uplift and Soil Yielding

In order to evaluate the dynamic behavior of the abutment with footing uplift and soil yielding, this paper analyzed the seismic response of the abutment supported by spread foundation. In discrete element method, the soil and abutment system is simulated by mass-spring model, and the pounding between the girder and the abutment, the elastic-plastic response of the back-fill soil and the underlying soil is modeled by the nonlinear spring. Moreover, the Winkler soil spring is used to simulate the interaction between the abutment footing and the underlying soil. After comparing the results, it is shown that the effect of uplift seismic isolation is significant in reducing the plastic deformation of abutment stem at the plastic hinge regions. The yielding of underlying soil decreases the plastic deformation of abutment stem also, at the same time increases the effect of foundation uplift. However, the settlement induced by the yielding of underlying soil will make the tilt of abutment.