连续桥梁三维隔震体系地震反应分析

Earthquake Response Analysis of Three-Dimensional Isolated Systems for Continuous Bridges

基于刚性地基假定分别建立了隔震及非隔震条件下的三跨连续梁桥三维有限元模型,通过对该两种模型进行动力特性和动力时程反应分析,验证了三维隔震桥梁的水平及竖向隔震效果,研究了支座参数、多向地震作用和桥墩高度等因素对桥梁结构的地震反应及支座隔震效果的影响。结果表明,三维隔震支座对输入地震波的频率具有一定的敏感性;水平隔震效果随支座屈服前后刚度比的增大而增加;随着桥墩高度的增大,水平隔震效果逐渐增加,但增加趋势逐渐平缓;多向地震作用对水平隔震效果的影响很小,而对竖向隔震效果的影响不容忽视。

Three-dimensional finite element models of isolated and non-isolated three span continuous beam bridge were established on the basis of rigid foundation assumption. Through dynamic characteristics and timehistory response analysis of the two model, horizontal and vertical isolated effects of three-dimensional isolated bridge were validated. Influence of bearing parameters, multi-direction seismic action and height of pier on earthquake responses of bridge structures and isolated effect of isolator were studied. Results show that the three- dimensional isolator a certain degree of sensitivity on the input frequency seismic waves. Horizontal reduction efficiency will increase with the increase of the ratio of pre-yield and post yield stiffness of the isolator. With the increase of height of pier, horizontal isolation effect will increase but will be gently. The influence of multidirectional seismic action on horizontal reduction efficiency is verry small,but it can not be ignored on vertical.