大跨度铁路斜拉桥斜拉索参数振动分析  

Research on Parametric Oscillation of Cables for Long Span Railway Cable-stayed Bridge

作　　者：杨咏漪[1] 陈克坚[1] 

机构地区：[1]中铁二院工程集团有限责任公司,成都610031

出　　处：《铁道工程学报》2013年第10期60-65,91,共7页Journal of Railway Engineering Society

摘　　要：研究目的:随着铁路斜拉桥跨径的增大拉索参数振动问题逐渐显现出来,本文以渝利铁路韩家沱长江大桥为工程背景,计算了该桥的动力特性,讨论了垂度效应对拉索模态的影响,通过频率比较得出了易于发生参数振动的拉索,并通过有限元和数值积分两种方法讨论了各种因素(激励频率、激励振幅、阻尼)对索参数振动的影响,为设置拉索的抑制振动装置提供了一定的理论依据。研究结论:(1)随着斜拉索倾角的变小,垂度效应对索自振频率的影响越大,因此在进行拉索参数振动分析时一定要考虑斜拉索自重所产生的垂度效应影响;(2)当拉索频率和全桥频率成一定比率时,极易发生大幅度参数振动,对桥梁的使用和安全有不利影响;(3)参数共振机制主要受系统非线性关系而非阻尼的影响,故调整局部结构间的频率关系比增加阻尼对于抑制斜拉索参数共振往往更为有效、合理;(4)激励幅值对参数振动幅值有明显的影响,在抗风设计时应严格控制桥塔和梁体周期性振动(如涡激振动);(5)研究成果对设置拉索抑制振动装置具有一定的参考价值。Research purposes： With the increase of railway cable - stayed bridge span, the problem of cables parametric oscillation have gradually appeared. This dissertation is based on the Hanjiatuo Changjiang River Bridge of Yuli railway project. Finite element model is built to obtain the global modes. Also, the modes of the cables are calculated and by comparing the cables in which parametric oscillation may occur are found out. Two methods including finite element method and numerical integration are used to analyze the influences of various factors （frequency and amplitude of the excitation, damper） ,which provided a theoretical basis for vibration suppression device of cables. Research conclusions： （ 1 ） With the cable inclination smaller, the effect on the frequency of cable is greater. So the parametric oscillation must consider the effect of the cable - stayed dead weight sag. （2） The parametric oscillation will be very likely to happen when the frequencies of the cables is proportional to the global frequencies, which can do harm to the security and durability of the bridges. （ 3 ） Parametric resonance mechanism is mainly influenced by the non - linear relationship of the system rather than damping, so adjust the frequency relationship between the local structure than increase the damping, which is more effective and reasonable for the inhibition of the cable parametric oscillation. （4） Excitation amplitude has evident influence on the parameters of vibration amplitude, should strictly control the pylon and girder periodic vibration in wind resistance design （such as vortex induced vibration）. （5）The dissertation providedcertain specified significance for cable suppression device.

关 键 词：铁路 斜拉桥 拉索 参数振动 数值积分 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]