塔梁固结斜拉桥抗震性能研究

Research on Seismic Performance of Cable-stayed Bridge with Tower Beam Consolidation

大跨度塔梁固结斜拉桥的抗震性能通常弱于漂浮体系斜拉桥,由此造成的地震作用下结构受力状态较差,因此为确保塔梁固结斜拉桥在地震响应下的抗震性能,以主跨为150 m的塔梁固结斜拉桥为工程背景,利用midas Civil 2021有限元软件建立塔梁固结斜拉桥全桥的空间动力分析模型,基于控制变量法进行塔梁固结斜拉桥抗震性能分析,分别研究支座屈服刚度、支座底部滑动摩擦系数以及结构阻尼比对斜拉桥固定墩墩底弯矩、桩基础弯矩以及支座最大滑动位移量的影响规律。结果表明,随着支座屈服刚度和支座底部滑动摩擦的增大能够减小支座滑动位移,但是增大了桥墩底部和桩基础的弯矩,而结构阻尼比的增大能提高塔梁固结斜拉桥抗震性能,因此根据分析抗震设计参数组合取屈服刚度15000 kN/m、摩擦系数0.03以及结构阻尼比0.05,能够提高塔梁固结斜拉桥抗震性能,也为类似工程抗震设计提供借鉴参考。

The seismic performance of long-span tower girder consolidated cable-stayed bridges is usually weaker than that of floating system cable-stayed bridges,and the resulting structural stress state is poor under earthquake action.Therefore,in order to ensure the seismic performance of tower girder consolidated cable-stayed bridges under earthquake response,a tower girder consolidated cable-stayed bridge with a main span of 150 m is taken as the engineering background.midas Civil 2021 finite element software is used to establish the spatial dynamic analysis model of the whole bridge of the tower beam consolidated cable-stayed bridge.The seismic performance of the tower beam consolidated cable-stayed bridge is analyzed based on the control variable method.The influences of bearing yield stiffness,sliding friction coefficient at the bottom of the bearing and structural damping ratio on the bending moment at the bottom of the fixed pier of cable-stayed bridge,the bending moment of pile foundation and the maximum sliding displacement of the support are studied respectively.The results show that with the increase of bearing yield stiffness and sliding friction at the bottom of the support,the sliding displacement of the support can be reduced,but the bending moment of pier bottom and pile foundation can be increased,and the increase of structural damping ratio can improve the seismic performance of the tower girder consolidated cable-stayed bridge.Therefore,according to the analysis of seismic design parameters,the combination of yield stiffness of 15000 kN/m,friction coefficient of 0.03 and structural damping ratio of 0.05 can improve the seismic performance of the tower girder consolidated cable-stayed bridge,and provide a reference for the seismic design of similar engineering.