山区非等高三塔斜拉桥纵向抗震约束体系研究

摘要

Pingtang Bridge was taken as an example to find out the appropriate longitudinal seismic constraint system of mountain cable-stayed bridge with three different-height pylons, and nonlinear time history analysis was used in the study. Firstly, based on longitudinal seismic response of the structure, by comparing different longitudinal constraint systems, a more rational longitudinal constraint system was taken. Then four fluid viscous dampers were set on the both side pylons, and the rational parameters of fluid viscous dampers were obtained, based on parameter sensitivity analysis of fluid viscous dampers. In addition, different parameters of fluid viscous dampers were used on both side pylons with height differences, and further optimized the force and displacement of the structure. The results show that fluid viscous dampers installed on both side pylons, and selecting appropriate parameters, can effectively mitigate the force and displacement of the structure. By both side pylons using different parameters of fluid viscous dampers, the force of three pylons can be minimized at the same time, and the force of side pylons and mid pylon can be better balanced.%为确定山区非等高三塔斜拉桥合理的纵向抗震约束体系,以平塘特大桥为研究背景,采用非线性时程分析法进行研究.基于结构纵向地震反应,通过对比不同约束体系在地震作用下的响应,选取较为合理的纵向约束体系;通过在两边塔处设置液体黏滞阻尼器来减小结构的地震响应,并进行液体黏滞阻尼器参数敏感性分析,选取较为合理的阻尼器参数;在此基础上,通过对存在塔高差异的两边塔采用不同参数的液体黏滞阻尼器,进一步优化结构受力和位移.研究结果表明:在两边塔处设置液体黏滞阻尼器可以显著减小纵向地震作用下结构的内力和位移;通过两边塔采用不同参数的液体黏滞阻尼器,可以使三主塔所受内力均较小,且边塔可以更好地分担中塔受力.