防落梁板式橡胶支座抗震性能分析

Analysis of Seismic Performance of a Unseating-prevention Laminated Rubber Bearing

针对板式橡胶支座在地震作用下存在落梁风险的问题,开发了防落梁板式橡胶支座(unseating-prevention laminated rubber bearing,URB).在介绍该支座基本情况的基础上,以高烈度区典型预制桥梁为例进行罕遇地震作用分析,并对该支座的基本参数进行了研究.分析结果表明:该防落梁板式橡胶支座可通过钢丝绳限制桥梁上、下部结构间发生过大的相对位移,既可保护支座,又能降低落梁风险;虽然会增大桥墩的地震响应,但通过调整钢丝绳参数可降低这种不利影响;钢丝绳初始间隙和拉伸刚度是该防落梁板式橡胶支座的主要参数,初始间隙要同时满足正常使用和地震作用的要求,拉伸刚度应结合支座本身及桥墩受力确定.

A unseating-prevention laminated rubber bearing （URB） was developed to solve the problem that girder falling might be caused by the failure of laminated rubber bearing （RB）. Based on introduction of URB, seismic analysis of a typical precast bridge with URB in the high-intensity seismic zone under rare earthquake was done and parameters of URB were studied afterwards. Results show that relative displacement between the superstructure and the substructure of the bridge can be controlled by wire rope of URB to protect the bearings and reduce the risk of girder failing; although seismic response of pier can be increased by URB, this adverse effects can still be reduced by adjusting parameters of the wire rope ; initial gap and tensile stiffness of the wire rope are basic parameters of URB, where the former should meet the demands of normal using and earthquake, and the later can be determined by considering seismic response of URB and the pier together.