大跨度斜拉桥最大双悬臂施工阶段的抖振控制措施研究  

Buffeting-Restraining Measures for Long Span Cable-Stayed Bridges at the Longest Double Cantilever Construction Stage

作　　者：苏振宇 彭江辉 SU Zhenyu;PENG Jianghui(Hunan Provincial Communications Planning,Survey＆design InstituteCo,Ltd,Changsha,Hunan410008,China)

机构地区：[1]湖南省交通规划勘察设计院有限公司,湖南长沙410008

出　　处：《公路工程》2018年第3期146-151,共6页Highway Engineering

摘　　要：斜拉桥在最大双悬臂施工状态时,结构的刚度和阻尼都很低,在紊流风的作用下悬臂端会产生较大的抖振响应。本文采用耦合抖振响应分析的有限元CQC方法,以某斜拉桥为例计算了最大双悬臂施工阶段采用临时风缆与临时墩两种控制措施的抑振效果,并详细探讨了不同风缆布置方案与不同临时墩布置位置对抖振控制效果的影响。计算结果表明:临时风缆的抑振效果对风缆与水平方向的夹角并不敏感;风缆交叉布置会使主梁竖向和横向抑振效果都有所减弱;当风缆中的应力达到一定程度后,增大应力并不能有效的提高抑振效果;当风缆应力一定,增大风缆面积能显著提高抖振抑制效果,但也会使主梁根部横桥向弯矩增大,对塔梁临时固结处产生不利影响;临时墩的减振效率大大优于临时风缆;临时墩的布置位置不宜离桥塔太近,且宜在1/2悬臂长度外合理地质条件处布置。The stiffness and damping of a cable-stayed bridge are very low at the longest double cantilever construction stage,and a relatively high buffeting response at the end of cantilever occurs under the action of turbulent wind. Based on the finite element and CQC method of coupled buffeting analysis,the response suppression effects are calculated by introducing temporary wind cables and setting temporary piers at the longest double cantilever construction stage of a cable-stayed bridge. Moreover,the effects of different setting cases of wind cables and different positions of temporary piers are discussed in detail. The results show that the response suppression effects of temporary wind cables are not sensitive to the horizontal angle, and the vertical and lateral response increase when the cables are installed across. When the temporary wind cables reach a certain level of stress,increasing stress can＇ t improve the vibration suppression effect efficiently. By increasing the size of temporary wind cables,the buffeting response can be significantly suppressed. Meanwhile it also makes the lateral bend moment at the root of the main beam increase,which is harmful to the consolidation between beam and tower. The suppression effect of temporary piers is much better than that of wind cables. The temporary piers should not be arranged too close from the tower,and it is better to arrange them where there are reasonable geological conditions out of the half length of cantilever.

关 键 词：最大双悬臂 抖振控制措施 有限元CQC方法 临时风缆 临时墩 

分 类 号：U445[建筑科学—桥梁与隧道工程]