近断层高速铁路简支梁桥减隔震研究

Research on Seismic Isolation of Simple-Supported Beam Bridge for High-Speed Railways near Faults

摘要:

在地震带分布密集地区，近年来我国建设了高速铁路桥梁。邻近断层高速铁路桥梁有遭受强地震破坏的风险。如2022年青海门源地震为例，硫磺沟高速铁路简支梁桥受损严重，以致兰新高铁停运，可见，对近断层地震动作用下确定合适的高铁简支梁桥抗震体系，已成为当前强震区近断层高速铁路桥梁抗震设计的亟须解决的问题。采用双曲面球型减隔震支座和环型钢阻尼减隔震支座，对近活动断层简支梁进行抗震设计，发现后者对位移的控制能力更强。在8度罕遇地震作用下，其纵桥向剪力减震率为45%～83%；弯矩减震率为52%～83%，支座最大位移为247 mm。优先推荐近断层区采用环型钢阻尼减隔震支座。

Abstract:

High-speed railway bridges have been built in China in recent years in areas with dense seismic zones. High-speed railway bridges near faults are at risk of strong earthquake damage. Taking the 2022 Menyuan earthquake in Qinghai Province as an example, the simple-supported beam bridge of the Liuhuanggou High-Speed Rrailway was seriously damaged, so that the Lanzhou-Xinjiang High-Speed Railway was suspended. It can be seen that the determination of the appropriate seismic system of the high-speed railway simple-supported beam bridge under the action of near-fault ground motion has become an urgent problem to be solved in the seismic design of near-fault high-speed railway bridges in strong earthquake areas. The hyperboloid spherical seismic isolation bearing and the ring steel damping seismic isolation bearing are used to carry out the seismic design of the simple-supported beam near the active fault. It is found that the latter has a stronger ability to control displacement. Under the 8 degree rare earthquake, the longitudinal shear damping rate is 45%~83%. The damping ratio of the bending moment is 52%~83%, and the maximum displacement of the bearing is 247 mm. Annular steel damping seismic isolation bearings are recommended as the priority option for application in near-fault areas.