特大跨斜拉桥横向抗震设计方案研究

Study on Lateral Seismic Design Scheme of Super-long-span Cable-stayed Bridge

摘要:

针对大跨度斜拉桥在高烈度横向地震作用下的抗震分析，就现今工程中常用到的添加挡块、金属阻尼器、黏滞阻尼器这3种减震设计方法，以某特大跨铁路斜拉桥为工程背景，基于MIDAS Civil建立了三维有限元动力弹性模型，分析了桥梁结构的动力特性；通过采用3种参数化后的方案与梁墩横向自由边界条件下的对比分析，研究了满足横向极限位移控制条件下，3种设计方案的结构地震响应特点；另外针对黏滞阻尼器和金属阻尼器减震方案，对2种阻尼器组合和布设方案进行了局部优化。研究结果表明：增设挡块减震方案要比采用阻尼器减震方案的墩塔底部内力大，采用黏滞阻尼器设计方案的减震效果最好；经过综合比较后，推荐采用组合1方案（过渡墩和辅助墩的左右侧分别设置金属阻尼器、液体黏滞阻尼器）用于铁路大跨斜拉桥。

Abstract:

Aiming at the anti-seismic analysis of long-span cable-stayed bridge under the high-intensity lateral earthquake, three design methods of adding the baffle plate, metal damper and viscous dampers are commonly used in the current projects. Based on MIDAS Civil, a three-dimensional finite element dynamic elastic model is established to analyze the dynamic characteristics of the bridge structure. By comparing and analyzing the three parameterized schemes with the transverse free boundary conditions of the beam pier, the characteristics of the structural seismic response of the three design schemes under the control of the lateral ultimate displacement are studied. For the damping schemes of viscous damper and metal damper, the local optimization of the two damper combinations and layout schemes is carried out. The results show that the internal force at the bottom of pier pylon of damping scheme adding the baffle plate is larger than that of damper scheme. The damping effect of the viscous damper design scheme is the best. After the comprehensive comparison, the combination scheme 1 is recommended for the railway long-span cable-stayed bridge.