组合梁斜拉桥施工最大单悬臂阶段抖振响应及减振研究  

Study of Buffeting Response and Suppression Measures for Composite Girder Cable-Stayed Bridge in Longest Cantilever State During Construction

作　　者：胡旭辉[1] 杨申云 李郁林 王骑[2] HU Xu-hui;YANG Shen-yun;LI Yu-lin;WANG Qi(School of Civil Engineering and Architectures,Chongqing Jiaotong University,Chongqing 400074,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 630031,China;Hunan Provincial Communications Planning,Survey&Design Institute Co.,Ltd.,Changsha 410219,China)

机构地区：[1]重庆交通大学土木建筑学院,重庆400074 [2]西南交通大学土木工程学院,四川成都630031 [3]湖南省交通规划勘察设计院有限公司,湖南长沙410219

出　　处：《桥梁建设》2021年第1期21-28,共8页Bridge Construction

基　　金：国家自然科学基金项目(51678508,51778547)。

摘　　要：为确保大跨度组合梁斜拉桥主梁最大单悬臂阶段在风荷载作用下的施工安全,对该阶段主梁的抖振响应及其减振措施进行研究。以某主跨650m的组合梁斜拉桥为背景,采用CQC(完全二次型组合法)计算施工最大单悬臂阶段主梁抖振响应,结果表明在20m/s风速下主梁悬臂端竖向抖振加速度超过限值。提出采用柔性拉索连接两悬臂端的“软连接”减振措施。对6种不同“软连接”方式的减振效果进行分析。结果表明:“软连接”可通过联动作用使悬臂端的振动相互制约,可有效降低悬臂端竖向和横向抖振响应;空间交错组合连接减振效果最好,竖向和横向振幅分别降低35%和62%,平面交错连接次之,竖向和横向振幅分别降低35%和31%;“软连接”缆索长度增长后,减振效果会显著降低,需根据现场实际情况选择使用。When the construction of long-span composite girder cable-stayed bridge comes into the longest cantilever state,winds are big safety challenges.The buffeting response of the superstructure in this phase and suppression measures are studied.The complete quadratic combination(CQC)method is used to compute the buffeting response of the superstructure of a real bridge in the longest cantilever state,which is a composite girder cable-stayed bridge with a main span of 650m.The results indicate that the acceleration of cantilever-end vertical buffeting response of the superstructure exceeds the limit value at the wind speed of 20m/s.A kind of“flexible-connection”buffeting suppression measure is proposed,by which the two ends of the cantilever are connected with flexible ropes.The buffeting mitigation effects of six types of flexible connection are analyzed.The results show that flexible connection allows the vibrations at the cantilever ends under reciprocal restriction via coupling effects,leading to effective reduction of vertical and transversal buffeting responses at the cantilever ends.The space cross-connection can present the best buffeting suppression effect,with vertical and transversal vibration amplitudes reduced by 35%and 62%,respectively.Though not as effective as the space-cross connection,the plane-cross connection enables the vertical and transversal vibration amplitudes to reduce by 35%and 31%,respectively.Elongation of the ropes in the flexible connection system results in the reduction of the buffeting suppression effect,therefore,the lengths of the ropes should be determined depending on the actual construction demands.

关 键 词：斜拉桥 组合梁 抖振响应 悬臂端“软连接” 施工最大单悬臂阶段 减振措施 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U441.3[交通运输工程—道路与铁道工程]