Effect Of The Back Wall Of Abutment On The Seismic Response Of Bridge

Bridge,as a lifeline project,plays a vital role in earthquake relief.With the deepening of bridge seismic research,China needs to improve the research on the interaction of "abutment-fill" to supplement the blank of China's seismic standard.This topic will adopt multi-model and multi-platform technology method,based on Abaqus numerical simulation to study the failure mode and law of abutment structure under load.The hysteretic curve of force-displacement relationship of abutment structure is obtained by applying cyclic load.The calculation formula of abutment back wall mechanical model is introduced and simplified.The simplified mechanical model is combined with the mechanical model of abutment back fill in CALTRANS seismic design standard,so that it can be used as a simple spring model in OpenSees software to analyze the seismic response of the example bridge.In this paper,the failure mode of abutment structure under load is studied by Abaqus finite element software,and the influences of abutment size,arrangement of reinforcement bars and other factors on the failure mode and crack development of abutment under longitudinal load of main girder are analyzed.By applying cyclic load to the abutment,the force-displacement hysteresis curve of the abutment is obtained.Based on the research results of the transverse reinforced concrete,the calculation formula of abutment back wall mechanical model is introduced.The applicability of the calculation formula to abutment back wall structure is verified according to the force-displacement relationship,and the calculation formula is further simplified and checked.The bridge seismic response analysis is carried out in the open finite element software OpenSees.The influence of seismic action on the displacement of superstructure and the influence on the displacement ductility coefficient of pier column are obtained under different simulation methods for abutment-backfill.The practicability of the simplified formula and the contribution of abutment back wall under seismic action are further analyzed.