泰州长江公路大桥振动台试验--试验设计及抗震结构体系试验结果分析

摘要

In order to study the optimal seismic structural system of long-span multi-pylon suspension bridges,a 1∶40 scale model of Taizhou Changjiang Highway Bridge is designed,constructed and tested on the shake table.Three seismic structural systems,including free system,viscous damper system and elastic cable system,are designed by installing different connecting devices between the main girder and the middle pylon.The bridge seismic responses of the three systems are tested under earthquake excitation.The experimental results show that the fundamental frequencies and damper ratios of the three systems are identified by structural responses under white noise excitations.Dis-placement responses of the pylon top and the relative displacement responses between the pylon and the main girder of the viscous damper system and elastic cable system are less than those of the free system.Under the site specific artificial wave,the relative displacement responses between the north pylon and the main girder are reduced to a greater extent by the viscous damper system.However, the relative displacement responses between the middle pylon and the main girder are reduced more by the elastic cable system.The conclusions are valuable for the seismic design of long-span multi-pylon suspension bridges.%为了研究大跨多塔悬索桥合理抗震体系，以泰州长江公路大桥为背景，设计并制作了1∶40缩尺比例模型，进行了全桥振动台模型试验。通过改变中塔与主梁间的连接方式，建立了无约束体系、阻尼器体系和弹性索体系等3个试验模型，并分别测试了其全桥地震反应。试验结果表明，利用白噪声对结构进行扫频，可以识别3种纵向约束体系的一阶频率和阻尼比。与纵向无约束体系相比，阻尼器体系和弹性索体系能够不同程度地减小塔顶位移和塔、梁相对位移。阻尼器体系可以更均衡地限制在场地人工波激励下中塔和边塔处的塔、梁相对位移；而弹性索体系限制中塔处塔、梁相对位移的能力更优。研究结果对大跨多塔悬索桥抗震设计具有一定的参考价值。