开槽两侧格栅对分体双箱梁涡激振动控制研究  

Vortex induced vibration control of split twin-box girder with grilles on both sides of opened slot

作　　者：段青松 马存明[2,3] 徐召 DUAN Qingsong;MA Cunming;XU Zhao(School of Civil Engineering and Architecture,Southwest University of Science and Technology,Mianyang 621010,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Wind Engineering Key Laboratory of Sichuan Province,Chengdu 610031,China;Shandong Provincial Communciations Planning and Design Institute Group Co.,Ltd.,Jinan 250161,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]西南交通大学土木工程学院,成都610031 [3]风工程四川省重点实验室,成都610031 [4]山东省交通规划设计院集团有限公司,济南250161

出　　处：《振动与冲击》2024年第21期64-70,95,共8页Journal of Vibration and Shock

基　　金：国家重点研发计划项目(2022YFC3005300);国家自然科学基金资助项目(520191258);风工程四川省重点实验室开放课题基金(WEKLSC202302);西南科技大学自然科学基金项目(21ZX7148)。

摘　　要：分体双箱梁断面涡激振动性能及优化是大跨桥梁抗风设计面临的关键问题之一。以某大跨度悬索桥为背景,针对分体双箱梁制作节段模型进行风洞试验,分析不同攻角时主梁涡激振动性能,提出在开槽两侧沿主梁纵向对称布置气动格栅的优化方案,研究主梁开槽两侧格栅的透风率对涡激振动性能影响规律。结果表明:当阻尼比为0.25%,攻角为-3°、0°和+3°时,主梁竖向涡激振动的无量纲最大振幅分别为0.032、0.033、0.023;当攻角为0°和-3°时,主梁扭转涡激振动最大振幅分别为0.18°、0.13°。开槽处布置透风率50%的两侧格栅后,主梁竖向涡激振动消失。这是由于气流在上游断面迎风侧前缘及栏杆处发生分离,产生较大尺寸的上部旋涡,随着旋涡不断运动,与下游断面发生碰撞,同时主梁尾流产生交替脱落的旋涡,诱导分体双箱梁断面发生涡激振动。开槽两侧布置两侧格栅后,气流的分离作用被弱化,在开槽位置处旋涡尺寸明显减小,减弱对下游断面的作用,优化主梁的涡激振动性能。研究可为分体双箱梁抗风设计提供参考。Vortex induced vibration(VIV)performance and optimization of split twin-box girder section are one of key problems faced by anti-wind design of long-span bridges.Here,taking a large-span suspension bridge as the background,wind tunnel tests were conducted for a segmented model of split twin-box girder to analyze VIV performance of its main beam under different attack angles.An optimization scheme was proposed to symmetrically arrange aerodynamic grilles along main beam longitudinal direction on both sides of opened slot to study effects of grilles’ventilation rate on VIV performance of main beam.The results showed that when damping ratio is 0.25%and attack angles are-3°,0°and+3°,dimensionless maximum amplitudes of VIV of main beam are 0.032,0.033 and 0.023,respectively;when attack angles are 0°and-3°,maximum amplitudes of torsional VIV of main beam are 0.18°and 0.13°,respectively;after arranging grilles with ventilation rate of 50%on slot both sides,vertical VIV of main beam disappears,it is because airflow separates at leading edge of windward side of upstream section and railing to generate larger upper vortices;with vortices continuously moving,they collide with downstream section,main beam wake generates alternating shedding vortices to induce VIV of split twin-box girder section;after arranging grilles on slot both sides,the separation action of airflow is weakened,and vortex sizes at slot position obviously decrease to weaken their action on downstream section and optimize VIV performance of main beam;the study can provide a reference for anti-wind design of bridges with split twin-box girder section.

关 键 词：分体双箱梁 风洞试验 涡激振动 格栅 绕流结构 

分 类 号：U441.3[建筑科学—桥梁与隧道工程]