Experimental Study on Seismic Performance of Concrete Continuous Bridge with HDR Bearings

Abstract

Several earthquakes have shown that concrete continuous bridges suffer from major damage and permanent deformations. This paper investigates the use of high damping rubber (HDR) bearings to improve seismic performance of concrete continuous bridge. The shaking table array test of a two-span isolated continuous bridge specimen with 1:3 scale was carried out to study the seismic response characteristics of the continuous bridge with HDR bearing isolation. The experimental results were compared with the seismic response of non-isolated continuous girder bridge specimen. The results indicated that the seismic response of continuous girder bridge varied with input ground motion, direction and PGA. In terms of HDR bearing isolation system, there was time lag between seismic responses of the upper and lower structures, and the acceleration of the side pier was larger than that of the middle pier while displacement response has better symmetry than non-isolated specimen. The effect of vibration isolation varied with shaking frequency, intensity and direction. The seismic damage was mainly concentrated in the bottom of the middle pier column and the middle bearing. The horizontal shear capability model of the HDR bearing is proposed as the bilinear restoring force model. The numerical analysis model of the bridge specimen established on the simplified bearing model can reflect the damping effect of the HDR bearing on the concrete continuous bridge.