大跨铁路桥窄幅流线型箱梁涡激振动试验及抑振措施研究  

Research on Vortex-Induced Vibration Tests and Mitigation Measures for Narrow Streamlined Box Girders in Long-Span Railway Bridge

作　　者：段青松 马存明[2] 何知明 DUAN Qingsong;MA Cunming;HE Zhiming(School of Civil Engineering and Architecture,Southwest University of Science and Technology,Mianyang 621010,China;Department of Bridge Engineering,Southwest Jiaotong University,Chengdu 610031,China;Hanbanan Intercity Railway Co.,Ltd.,Bazhong 636099,China)

机构地区：[1]西南科技大学土木工程与建筑学院,四川绵阳621010 [2]西南交通大学桥梁工程系,四川成都610031 [3]汉巴南城际铁路有限责任公司,四川巴中636099

出　　处：《桥梁建设》2024年第5期55-60,共6页Bridge Construction

基　　金：国家自然科学基金项目(52078438);西南科技大学自然科学基金项目(21ZX7148);风工程四川省重点实验室开放课题基金项目(WEKLSC202302)。

摘　　要：为有效抑制大跨铁路桥窄幅流线型箱梁的涡激振动,以某主跨335 m的窄幅流线型箱梁铁路斜拉桥为背景,设计、制作缩尺比1∶30的主梁节段模型进行风洞试验。研究不同风攻角、阻尼比下的主梁节段模型涡激振动性能,结合数值模拟法分析涡激振动诱因,并基于此进行抑振措施研究。结果表明:竖向阻尼比为0.20%时,-5°、-3°和0°风攻角下,主梁未出现涡激振动;+3°和+5°风攻角下,主梁出现竖向涡激振动,竖向涡激振动的最大无量纲振幅分别为14.4、19.4;增大竖向阻尼比可以有效抑制主梁的竖向涡激振动,但无量纲涡激振动风速区间基本未发生变化。栏杆基座是诱发主梁涡激振动的主要因素,栏杆基座与挡砟墙之间及栏杆后侧的分离涡主导主梁发生涡激振动,去除栏杆基座后桥面较大尺寸的分离涡被打散为小尺寸分离涡。封闭栏杆不能完全抑制主梁涡激振动,去除栏杆基座并优化为集水槽后,主梁迎风侧风嘴处气流的分离作用被弱化,可完全抑制主梁竖向涡激振动。This study focuses on the vortex-induced vibrations(VIVs)of narrow streamlined steel box girders of the long-span railway bridge.A railway bridge with a main span of 335 m is used as a case.A 1∶30 scale main girder segment model was prepared for wind tunnel tests,to investigate the VIVs of the main girder segment at different wind attack angles and under different damping ratios.Together with the numerical simulation,the causes of the VIVs were analyzed and vibration mitigation measures were studied.The main girder was not subjected to VIVs at a vertical damping ratio of 0.20%and at the wind attack angles of-5°,-3°and 0°.At wind attack angles of+3°and+5°,vertical VIVs were observed in the main girder,with maximum dimensionless vibration amplitudes of 14.4 and 19.4,respectively.Increasing the vertical damping ratio can effectively suppress the vertical VIVs,but the wind velocity ranges of the dimensionless VIVs showed no change.The plinths of railings were regarded as the main cause of VIVs,the vortex shedding between the railing plinths and the ballast walls as well as behind the railings was closely related to the occurrence of VIVs.After removing the railing plinths,the big vortices were continuously broken into smaller vortices.Sealing up the railings did not show effective mitigation of VIVs.When the rectangular plinths of the railings were removed,and the base of the railings were changed to be catch pits,the vortex shedding effect at the wind fairings on the windward side of the main girder was weakened,resulting in the complete mitigation of vertical VIVs of main girder.

关 键 词：铁路桥 斜拉桥 窄幅流线型箱梁 栏杆基座 涡激振动 抑振措施 风洞试验 数值模拟 

分 类 号：U448.13[建筑科学—桥梁与隧道工程] U448.27[交通运输工程—道路与铁道工程] U441.3