简支梁桥铅芯橡胶支座减震特性研究

Research on Seismic Isolation Characteristics of LRB for Simply Supported Beam Bridge

以一座4×40m简支T形梁桥为例,对常规非隔震设计的板式橡胶支座和减隔震设计的铅芯橡胶支座(LRB)进行对比分析,比较了2种支座设计下桥梁结构的动力特性以及采用隔震设计后桥梁结构内力、位移响应与非隔震设计的差别。在其他条件一致前提下,研究了铅芯橡胶支座的力学参数对减隔震效果的影响。研究结果表明:铅芯橡胶支座较板式橡胶支座设计的桥梁可以延长结构的周期;设计的铅芯橡胶支座具有明显的减震效果,铅芯橡胶支座可以大幅度减小各墩墩底剪力及墩底弯矩,各墩所受地震力重新合理分配且受力趋于平衡;同时在减隔震设计中,只考虑增大铅芯橡胶支座的型号反而会给桥梁下部结构带来不利的影响。

Taking a 4 × 40 m simply supported T-girder bridge as example ,comparative analysis of non-isolated design by conventional plate type elastomeric pad bearings and seismic isolation design by lead rubber bearing （LRB） was done ,and the bridge structure dynamic characteristics of the two bearing design were compared . Furthermore , the structural internal force and displacement response differences between isolation design bridge and non-isolation design were also compared . In other conditions consistent with the premise , the influence of mechanical parameters of LRB on seismic isolation was studied . Study results show that plate type elastomeric pad bearings design of LRB can extend the period of bridge structure ;the designed LRB has obvious damping effect ,and LRB can greatly reduce shear and moment at the pier bottom ,and each pier again tends to balance and reasonably distributes the seismic forces .In seismic isolation design , the blind pursuit of increasing LRB models will give the bridge substructure adversely affected .