九度地震区高速铁路简支梁合理减隔震体系分析

为了得到九度地震区典型高速铁路简支梁合理减隔震体系，提出了一种桥址区地震危险性贡献参数分析方法，运用核密度估计理论推导了一种桥梁地震易损性计算方法，建立一种基于地震风险评估的铁路桥梁抗震分析方法。以渝昆高铁九度地震区典型32 m预应力混凝土简支梁为研究对象，选取5种组合减隔震体系作为比选对象，运用基于地震风险的桥梁抗震分析方法，全面评估了5种减隔震体系的适应性。结果表明：采用双曲面减隔震支座+榫形金属减震耗能装置+钢防落梁组合减震方案时，桥墩和支座的地震损伤风险发生概率可分别控制在6%和3%以内，方案可有效提高桥墩抗震性能，耗散地震能量，减少桩基地震力，同时可以有效限制主梁位移，防止发生落梁震害，实现了九度地震区高速铁路32 m简支梁桥抗震设计，可为今后强震区类似桥梁抗震分析提供依据。

Analysis of reasonable seismic isolation system for high-speed railway simply supported bridge in nine-degree seismic regions

In order to obtain a reasonable seismic isolation system for typical high-speed railway simply supported bridge in nine-degree seismic regions, an analysis method for seismic hazard contribution parameter of bridge site was proposed, and a calculation method for seismic vulnerability of bridge was deduced by using kernel density estimation theory, then a seismic analysis method for railway bridge based on seismic risk assessment was established. Taking a typical 32 m prestressed concrete simply supported beam bridge in the nine-degree seismic region of Chongqing-Kunming high-speed railway line as the research object, five combined seismic isolation systems were compared and comprehensively evaluated by using the seismic analysis method based on seismic risk assessment. The results show that the seismic risk probabilities of piers and bearings can be controlled within 6% and 3% when the seismic isolation system composed of double spherical aseismic bearings, tenon-shaped metal energy dissipation devices and steel anti-drop-beam devices was used. This system can effectively improve the seismic performance of piers, dissipate the seismic energy, reduce the seismic force of pile foundations, and limit the displacement of main girders, then preventing girder falling and realizing the seismic design of 32 m high-speed railway simply supported bridge in nine-degree regions. It provides a basis for seismic analysis of similar bridges in high intensity seismic regions in the future.