Effect of Abutment on the Longitudinal Seismic Response of a Continuous Girder Bridge

Abstract:

Based on the prototype of a continuous girder bridge with Ushaped seat abutment with pile foundation, effect of girderabutmentbackfill interaction on longitudinal seismic response of a continuous girder bridge was studied by nonlinear time history method. The effects of abutment backwall in flexural yield mode or abutment backwall bottom in shear failure mode on longitudinal seismic responses such as the longitudinal displacement of bearing, the displacement ductility demand of pier and bending moment of abutment pile were investigated. Furthermore, parameter analyses on the yield moment of abutment backwall, the expansion joint clearance at the abutment and height of pier were carried out. Results show that the longitudinal displacement of bearing, the displacement ductility demand of pier and the bending moment of abutment pile in the case of abutment backwall bottom in shear failure mode are less than those in the case of abutment backwall in flexural yield mode obviously. As the yield moment of abutment backwall increases, the longitudinal displacement of bearing decreases and the displacement ductility demand of pier increases gradually and becomes stable while the moment of abutment pile increases gradually. As expansion joint clearance decreases, the longitudinal displacement of bearing decreases, while the displacement ductility demand of pier might increase.