南京仙新路特大跨度悬索桥抗震性能研究

鉴于大跨度悬索桥抗震性能研究的复杂性和特殊性,以南京仙新路特大跨度悬索桥为例,阐述悬索桥抗震性能研究的全过程,并分析行波效应对该桥地震响应的影响。结果表明:该桥的第一阶振型周期超过25.0 s,在常规体系E2地震下,桥塔及其基础保持弹性,但中央扣受拉破坏,从而使主梁位移过大;采用将中央扣作为牺牲构件,同时在塔梁间设置液压粘滞阻尼器的纵向减震体系后,能显著减小塔上支座、梁端的纵向位移以及主引桥相对位移,同时能小幅度减小塔底和承台底地震内力;行波效应对减震体系关键位置的地震内力和地震位移的影响较小。

Study on Seismic Performance of Nanjing Xianxin Road Super Long-span Suspension Bridge

The dynamic property and seismic response of long-span suspension bridge are all very complicated,and the dynamic property and seismic environment of each suspension bridge are all different.Therefore,it is necessary to study the seismic performance in detail.Taking a super long-span suspension bridge with the main span 1760 m in Xianxin Road of Nanjing as an example,this paper sets forth the whole process of the study on the seismic performance of suspension bridge and analyzes the impacts of traveling wave effect on the seismic response of this bridge.The results show that the first mode period of this bridge is beyond 25.0 s and belongs to the long period.In a conventional E2 earthquake,the bridge pylon and its foundations remain elastic,but the seismic axial force of the central buckle is too high and causes the tensile failure so as to make the main beam displacement too large.After adopting the central buckle as sacrificial component and also setting up the longitudinal damping system of hydraulic viscous damper between the pylon and beam,the longitudinal displacements of the pylon support and beam end,and the relative displacement of the main approach bridge can be obviously decreased,and meanwhile the earthquake-induced internal forces at the bottoms of the pylon and base slab can be reduced slightly.The traveling wave effect has little influence on the seismic internal force and seismic displacement at the key position of the damping system.