大跨PK断面钢箱梁斜拉桥涡振性能及优化措施研究  

Research on Vortex-Induced Vibrations of Long-Span Cable-Stayed Bridge with PK Section Steel Box Girders and Aerodynamic Shape Optimization Measures

作　　者：王存国[1] WANG Cunguo(China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China)

机构地区：[1]中铁第四勘察设计院集团有限公司,湖北武汉430063

出　　处：《世界桥梁》2024年第3期90-96,共7页World Bridges

基　　金：中国铁建重大专项(2020-A01);中铁第四勘察设计院集团有限公司科技研发计划项目(2022K084,2022K110)。

摘　　要：红莲大桥主桥为主跨580 m的双塔斜拉桥,中跨主梁采用PK断面钢箱梁,该类主梁断面易发生涡振,需对其涡振性能及抑振措施进行研究。基于该桥有限元动力特性分析结果,制作PK断面钢箱梁1∶60缩尺比节段模型进行测振风洞试验,研究桥梁原始设计断面主梁的涡振性能,讨论增加结构阻尼比(增加至0.010和0.027)措施的涡振抑振效果,并对增设稳定板、水平导流板、部分封闭桥面栏杆等不同气动优化措施及组合对主梁涡振性能的影响进行分析。结果表明:原始设计PK断面钢箱梁的涡振振幅明显超过规范限值;增大结构阻尼比虽然可以有效抑制涡振响应,但阻尼比增加至0.027时竖弯涡振振幅仍然显著;在桥面检修栏杆上缘外挑1.6 m宽水平导流板可将涡振振幅降低到可忽略的水平;采用在检修栏杆上缘外挑1.1 m宽水平导流板、优化桥面燃气管道位置、调整防撞护栏下部封闭高度为0.42 m,或移除检修道栏杆底座、错列布置封闭检修道栏杆和防撞护栏等组合措施,虽不足以完全抑制涡振的发生,但可将涡振振幅控制至明显小于规范限值。The Honglian Bridge is a two-pylon cable-stayed bridge.The main span,with a length of 580 m,consists of steel box girders of Pasco-Kennewick(PK)cross-section that are prone to vortex-induced vibrations(VIVs).The study in this paper focuses on the characteristics of VIVs and vibration mitigation measures.In accordance with the finite element analysis,a 1∶60 scale sectional model of PK section steel box girder was prepared for wind tunnel test.The characteristics of VIVs on the original cross-section of steel box girders in the main span were analyzed,and the vortex-induced vibration suppression effect of the bridge after improving the damping ratio of the structure(increasing to 0.01 and 0.027,respectively)was examined,and further analysis was conducted to investigate the effects of different aerodynamic shape optimization measures and measure combinations on the VIVs of the main girder.It is shown that the amplitudes of VIVs of the original PK section steel box girder remarkably exceed the limit values suggested in codes.Although increasing the damping ratio of the steel box girder can effectively suppress VIVs,the vertical vortex vibration amplitudes are still remarkable even when the damping ratio arrives at 0.027.Adding 1.6 m-thick horizontal deflectors on upper edges of balustrades can mitigate the amplitudes of VIVs to a negligible level.Effective measures also include adding 1.1 m wide horizontal deflectors on the upper edge of the balustrades,optimizing the locations of gas tubes in the superstructure,and allowing the closure depth of the crash barriers to be 0.42 m.Removing the footings of the crash barriers and staggeringly closing the crash barriers and balustrades are commonly-performed measures.None of these measures can totally suppress the occurrence of VIVs,but they can control the amplitudes of vortex-induced vibrations to below the code limits.

关 键 词：斜拉桥 PK断面钢箱梁 涡振 阻尼比 气动措施 节段模型风洞试验 

分 类 号：U443.35[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]