不等高桥墩铁路减隔震桥梁钢阻尼支座地震易损性

以设置E型钢阻尼装置的不等高桥墩高速铁路减隔震简支梁桥为对象,建立考虑轨道约束的全桥非线性有限元分析模型,并进行100条地震动作用下的非线性时程分析.从基于性能要求的抗震设计思想出发,采用位移和能量双重破坏准则,提出同时考虑最大变形效应和累积损伤效应两方面效应的钢阻尼支座损伤指标,采用可靠度概率分析方法形成钢阻尼支座在不同损伤状态下的易损性曲线.结果表明,地震作用下不同支座在各损伤状态下的易损性差异明显,对于桥墩高度差异较大的铁路减隔震桥梁,宜根据桥墩刚度的不同进行减隔震设计,对刚度较小的高、中墩处的钢阻尼支座,设计时应留有必要的安全储备.

Seimic fragility of steel damper bearings in isolatedrailway bridges with different-height piers

In this study, isolated high speed railway simply supported bridges with E-shape steel damper bearings and different-height piers were taken as example. Nonlinear FEM analysis model of the bridge were established. Nonlinear time-history analyses under 100 earthquake wave records were performed. From the principle of performance-based seismic design, and based on displacement and energy failure criterion, an approach for determining damage indexes of E-shape steel damper bearings both considering maximum deformation effect and accumulative damage effect was proposed. Through traditional reliability probability analysis method, the fragility curves of bearings under different damage status were constructed. The results show that the seismic fragilities of different bearings under every damage status have significant difference. For isolated railway bridges with significant difference in pier heights, seismic isolation device should be designed according to different pier stiffness. For the design of steel damper bearings on piers with high or medium height, adequate safety margin is necessary.