Full-scale pseudo-dynamic test for bridge retrofitted with seismic isolations

Abstract

The authors examine retrofitted bridge pier performance with a seismic isolation present. Retrofitted bridge seismic performance experimental validation was done through fabrication and testing of four full-scale reinforced concrete bridge piers with fixed support conditions. To simulate the superstructure dead load, a static vertical load was applied to the bearing top and several different bearing systems were installed. Conventional pot bearing was also considered in addition to lead rubber bearing (LRB) and rubber bearing (RB) systems. To simulate earthquake loading, a horizontal loading was applied to the specimen using a pseudo-dynamic testing method. Isolated RB and LRB system specimen seismic response was compared to that of the conventional pot bearing specimen. That the seismic isolation system this study considers is effective in magnitude reduction of transferred substructure forces and period bridge shifting is shown in the results. The peak acceleration transmitted to the structure can be effectively reduced by the LRB structure, which under earthquake loading is less than those with RB system. That the proposed seismic retrofit method was found to be valid can be concluded through the test results.