长联大跨摩擦摆支座隔震连续梁桥多维地震反应分析

结合长联大跨连续梁桥的特点,以1座(65+123+156+123+10×90+55)m长联大跨摩擦摆支座隔震连续梁桥为背景,建立了全桥三维有限元模型,运用非线性时程分析法,分析了地震动输入模式、地震动强度、摩擦摆支座参数对该桥内力、位移和能量响应的影响。研究结果表明:(1)长联大跨连续梁桥布置摩擦摆支座,可有效延滞固定墩顶有效主梁质量效应,实现全桥协同抗震。大部分地震能量可通过支座滞回耗能散耗,大幅降低了该桥固定墩地震能量耗散需求。(2)长联大跨连续梁桥减隔震设计中,建议采用水平单向+竖向地震组合进行内力设计,采用三向地震组合进行位移设计。(3)强震作用下,支座摩擦因数取0.029~0.034时该桥隔震性能最优。

Multi-dimensional seismic response analysis of long-span isolated continuous girder bridge with friction pendulum system

According to the characteristics of long span continuous girder bridge, a 3D finite element model of the bridge is established based on a long-span (65+123+156+123+10×90+55m) isolated continuous girder bridge with friction pendulum bearings. The effects of ground motion input conditions, ground motion intensity and friction pendulum bearing parameters on the internal force, displacement and energy response of the bridge are analyzed by using nonlinear time history analysis method. The results show that:(1) the friction pendulum support is arranged for the long span continuous girder bridge, which can effectively delay the mass effect of the main girder at the top of the fixed pier and realize the cooperative seismic resistance of the whole bridge. Most of the seismic energy can be dissipated by hysteretic energy consumption through the support. (2) In the design of long-span isolated continuous girder bridge, it is better to use one horizontal + vertical ground motion input combination in design of internal force demand, and to use three-dimensional ground motion input combination in the design of displacement demand. (3) The best performance is obtained for the bridge when the support friction coefficient is 0.029~0.034.