该文以五跨一联隔震连续粱桥为研究对象,探讨了具有明显脉冲效应的近场、远场长周期地震动作用对采用铅芯橡胶支座(LRB)及摩擦摆隔震支座(VPB)的连续梁桥地震反应(梁体及支座位移、桥墩内力等)的影响程度,明确长周期地震动作用对隔震装置隔震效果及碰撞效应的影响。研究结果表明:对于隔震连续梁桥,长周期地震动作用下,隔震支座对连续梁桥的隔震效果均有所下降,但FPB隔震结构的隔震效果优于LRB隔震结构;对于布设LRB隔震支座的隔震桥梁,在远场长周期地震动作用下梁体位移大幅增加,结构更易发生碰撞且碰撞力较大,远场长周期地震动对LRB隔震桥梁的地震反应更为不利。
The seismic response of Five-span isolated continuous bridges under far field and near field long-period ground motions are discussed. Lead rubber bearings (LRB) or friction pendulum bearings (FPB) are used in the bridges and the ground motions have significant pulse impacts. Comparing with an aseismic structure, the isolation effects of two isolated bridges are declined, and the seismic performance of an FPB structure is better than that of an LRB structure. Furthermore, the far field long-period ground motion has an adverse effect on an isolated continuous bridge with LRB in view of the larger displacement and internal force comparing with FPB bridges.