沪苏通长江公铁大桥斜拉索高阶振动控制研究  

Study of Higher-Mode Vibration Control of Stay Cables of Shanghai-Suzhou-Nantong Changjiang River Rail-cum-Road Bridge

作　　者：查道宏[1] ZHA Dao-hong(China Railway Major Bridge Engineering Group Co.,Ltd.,Wuhan 430050,China)

机构地区：[1]中铁大桥局集团有限公司,湖北武汉430050

出　　处：《桥梁建设》2022年第6期1-7,共7页Bridge Construction

基　　金：国家重点研发计划项目(2016YFE0202400);湖北省技术创新专项项目(2018AAA029)。

摘　　要：沪苏通长江公铁大桥主航道桥为主跨1092 m的公铁两用钢桁梁斜拉桥,最长斜拉索长576.5 m。由于该桥安装的外置式杠杆质量阻尼器位于斜拉索高阶振型节点附近,无法对长斜拉索高阶振动进行有效控制。为有效抑制该桥长斜拉索的高阶振动,在通过实测数据分析斜拉索高阶振动特性的基础上,提出一种安装减振锤的斜拉索高阶抑振措施,减振锤由索夹、锤头、钢绞线和防坠钢丝绳等组成,锤头提供质量,钢绞线提供刚度和阻尼。通过室内模型试验、实桥测试以及实桥监测对减振锤减振性能进行研究。结果表明:减振锤对斜拉索高阶振动有较好的控制效果,可对最长斜拉索(M36号)高阶振动主频附近的5个阶次模态振动进行有效控制;安装减振锤后,桥梁正常运营期间斜拉索的振动加速度控制在0.005g以下,台风“烟花”期间实测斜拉索最大振动加速度为0.012g。在外置式杠杆质量阻尼器与减振锤的协同工作下,该桥斜拉索的低、中、高阶振动均得到较好的抑制。The main navigational channel bridge of Shanghai-Suzhou-Nantong Changjiang River Rail-cum-Road Bridge is a steel truss girder cable-stayed bridge with a main span of 1092 m.The maximum stay cable length reaches 576.5 m.Due to that the external lever mass dampers are generally installed near the nodes of the higher-mode vibrations of stay cables,they could not perform effective control on the high-mode vibrations of the long stay cables.To effectively suppress higher-mode vibrations of the long stay cables,the characteristics of the higher-mode stay cable vibrations were analyzed with the measured data,and on the basis of which,a type of vibration-damping hammer that is efficient for higher-mode vibrations is proposed.The vibration-damping hammer consists of a cable clamp,a hammer head,steel strands and fall-arrest steel ropes,where the hammer head provides the required mass,and the steel strands are sources of additional stiffness and damping.The vibration damping performance of the hammer were examined by performance test,field measurement and long-term monitoring.It is shown that the vibration-damping hammers are a good option,which can effectively control the five modes of vibrations near the basic frequencies of higher-mode vibrations of the longest stay cable(M36).After instrumented with vibration-damping hammers,the vibration accelerations of stay cables in normal service conditon are below 0.005g.In typhoon"firework",the measured maximum vibration acceleration of stay cables was 0.012g.By the combined utilization of external lever mass dampers and vibration hammers,the higher-,intermediate-and lower-mode vibrations of stay cables are effectively suppressed.

关 键 词：斜拉桥 斜拉索 高阶振动 减振锤 抑振措施 室内模型试验 实桥测试 

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]