Seismic Responses of a Bridge Pier Isolated by High Damping Rubber Bearing: Effect of Rheology Modeling

Abstract

This study is aimed at evaluating seismic responses of a bridge pier isolated by high damping rubber bearing (HDRBs), subjected to intra-plate and inter-plate earthquake ground motion records. In this regard, a conventional bilinear model and two elasto-visco-plasticity-based rheology models (the original rheology model [36] and an improved rheology model proposed in the current study) of HDRBs have been utilized in this study. In the first part of the paper, the adequacy of the two elasto-visco-plasticity-based rheology models has been checked in predicting the mechanical behaviour of the HDRBs, subjected to sinusoidal loadings. The numerical results of the HDRBs have shown that the improved rheology model can predict the mechanical behaviour of the bearings in a quite better way in comparison to the original rheology model, particularly at higher shear strain levels of the bearings. In the second part, seismic response analysis of a 3-DOF bridge superstructure–pier–foundation (s–p–f) system has been evaluated. In the end, nonlinear dynamic analysis using a standard direct time integration approach has been carried out. The seismic responses of the s–p–f system considered in the current study are the pier and deck displacements, the shear force of the bridge pier, the shear strain of the bearing and the total hysteretic energy of the bearings. The analytical results have shown that the rheology modeling of HDRBs has a significant effect on seismic responses of bridge pier.