Seismic Performance Assessment of Girder Bridges with Composite Rubber Bearings

Abstract

Abstract The objective of this study is to analytically assess the effectiveness of a novel composite rubber bearing (CRB), which is proposed to enhance both the displacement and damping capacities of the laminated natural rubber bearing (LNB), in improving the seismic performance of girder bridges. Four numerical bridge models respectively with the unbonded and bonded LNBs and CRBs (i.e. ULNB, BLNB, UCRB, BCRB) are established based on the bearing restoring force models. Then, incremental dynamic analyses (IDAs) are performed to obtain the fragility functions and the estimated economic costs. The results show that the bearing fragilities of the two CRB bridges are between those of the two LNB ones, but the pier damage is obviously mitigated by the CRBs, leading to the lower system vulnerabilities and economic costs. Allowing bearing sliding can further reduce the damage probability of the piers, but enlarge that of the bearings especially for the collapse limit state.