大跨度连续钢桁梁桥摩擦摆支座减隔震设计分析

Design and Analysis of Friction Pendulum Bearings for Seismic Mitigation and Isolation of Long Span Continuous Steel Truss Girder Bridge

为改善大跨度连续钢桁梁桥的抗震性能,以(102+4×168+102)m的济南长清黄河大桥主桥为背景,结合其结构特点采用摩擦摆支座对该桥进行全桥隔震及连续墩隔震方案设计。采用通用有限元程序SAP2000建立该桥空间有限元模型,以3条人工地震波作为激励,采用非线性时程分析方法对未隔震及应用摩擦摆支座隔震后的桥梁结构响应进行对比,结果表明:全桥隔震、连续墩隔震2种方案中摩擦摆支座均能起到良好的减隔震效果且满足设计要求。与全桥隔震方案相比,连续墩隔震方案中墩底弯矩和支座水平位移略大,但经济性更好,故综合考虑减隔震效果、经济性、支座尺寸等因素,推荐采用等效滑动半径为4m的摩擦摆支座连续墩隔震方案对该桥进行减隔震设计。

To improve the seismic performance of long span continuous steel truss girder bridge ,the main bridge with span arrangement （102＋4 × 168＋102） m of the Changqing Huanghe River Bridge in Ji′nan w as cited as an example and in the light of the structural features of the bridge ,the friction pendulum bearings were selected for the design of the schemes of whole bridge seismic isolation and continuous pier seismic isolation for the bridge . T he spatial finite element model of the bridge was set up by the universal program SAP2000 ,the model was excited by three artificial seismic waves and the structural responses of the bridge that was not seismically isolated and that was seismically isolated by the friction pendulum bearings were analyzed and compared by the nonlinearity time‐history analysis method .The results of the analysis indicate that the friction pendulum bearings for both the schemes of whole bridge seismic isolation and continuous pier seis‐mic isolation can achieve good effect of the seismic mitigation and isolation and can meet the design requirements .As compared to the scheme of whole bridge seismic isolation ,the moment of the pier footings and the horizontal displacement of the bearings in the scheme of continuous pier seis‐mic isolation are slightly great ,but the scheme is more economic .In comprehensive consideration of several factors of the seismic mitigation and isolation effect ,economy and dimensions of the bearings ,it is recommended that the friction pendulum bearings with 4 m equivalent sliding radii for the scheme of continuous pier seismic isolation should be adopted for the seismic mitigation and isolation design of the bridge .