大跨径连续刚构桥抗震性能评价

以武汉在建天兴洲大桥南岸引线某大跨径连续刚构桥为研究对象,考虑桩-土-结构共用作用情况,运用大型有限元分析程序ANSYS对其动力特性进行了分析,得到了成桥状态下结构的自振特性及累计振型参与质量比,确定了运用反应谱法对地震作用进行振型组合时所必需的振型阶数。对该桥进行了地震反应谱分析,得到各概率地震作用下结构的反应最大值,并根据"三水准"设防原则,分析评价了该桥的综合抗震性能,为该桥的建设和抗震设计提供了参考,也为进一步研究该类桥型的抗震性能提供了分析基础。分析结果表明,该桥具有足够的抗震能力,能够满足预期的设计性能。

Evaluation on Antiseismic Performance of Long Span Continuous Rigid Frame Bridge

On the basis of the engineering design case of a long-span continuous rigid frame bridge which is a south approach of Tianxingzhou Bridge in Wuhan City,the dynamic characteristics of this kind of structure are analysed and studied using the finite element software package ANSYS and taking pier-earth-structure interacting into account.In this paper,dynamic characteristics and the effective mode participation mass under finish-bridge status are got,and the minimum number of modes for mode effective structural response spectrum analysis is determined.In addition, the maximum seismic responses of this bridge obtained from response spectrum method.Based on all of these characteristics mentioned above,according to three-level security principles,the antiseismic performance of this bridge is also evaluated.Results obtained in this paper can be served as useful guidelines to construction and seismic design of the bridge.This systematic work offers analytical basement and guidance on effective antiseismic design as well as theoretical research of this type of bridges.Results show that the bridge can offer enough antiseismic bearing capacity and meet the expected design goal.