不同纵向约束体系多塔悬索桥行波效应研究

Effect of wave passage on seismic response of multi-tower suspension bridge under different longitudinal constraint systems

为了研究行波效应对不同纵向约束体系大跨多塔连跨悬索桥地震响应的影响,本文以泰州长江公路大桥为背景,设计并制作1/40缩尺比例模型,进行了全桥振动台模型试验。试验设计了3种纵向约束体系:无约束体系;弹性索体系和阻尼器体系,分别测试了行波效应下3种约束体系多塔悬索桥的地震响应。比较3条不同地震波下考虑行波效应的结构地震响应,发现chichi波考虑行波输入时会极大地增加结构的位移,泰州波输入增加程度次之,EI Centro波输入甚至会减小结构的位移。比较无约束、弹性索和阻尼器体系3种结构体系下行波效应对结构地震响应的影响,发现弹性索和阻尼器体系受行波效应影响的程度更大。试验结果表明,行波效应对结构响应的影响与结构自身特性以及地震波特性密切相关。数值结果与试验结果吻合较好,说明此数值模拟方法可用于大跨度桥梁行波效应分析。

To study the response of a long-span multi-tower continuous suspension bridge to seismic waves,we designed and constructed a 1/40 th scale model of the Taizhou Changjiang Highway Bridge and tested it on a shaking table for three different longitudinal constraint systems： a free system,an elastic-cable system,and a damper system. By comparing the displacement response of the bridge model to different seismic events,we found that the structural displacement greatly increased in response to a recording of the Chi-Chi earthquake,followed by the Taizhou earthquake. However,the structural displacement decreased in response to a recording of the El Centro earthquake. By comparing the displacement responses of the bridge model with the free,elastic-cable,and damper constraint systems,we found that the elastic-cable and damper systems led to the seismic wave having a more serious influence on the displacement than did the free system. The results show that the response of the bridge model to a seismic event depends on the characteristics of the bridge structure and the earthquake wave. Numerical results agree well with the test results,showing that numerical simulation can be used to analyze the effect of a seismic wave on a long-span bridge.