带挑臂PK箱梁涡振性能及优化措施机理研究  

VIV Performance and optimization measure mechanism of PK box girder with cantilever arm

作　　者：李春光[1] 贺小龙 黄笑 颜虎斌 韩艳[1] LI Chunguang;HE Xiaolong;HUANG Xiao;YAN Hubin;HAN Yan(School of Civil Engineering,Changsha University of Science&Technology,Changsha 410114,China)

机构地区：[1]长沙理工大学土木工程学院,长沙410114

出　　处：《振动与冲击》2024年第11期41-49,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金资助项目(51978087;51822803);长沙理工大学桥梁工程安全控制教育部重点实验室开放基金(18ZDXK09)。

摘　　要：为研究带挑臂PK箱梁的涡振性能及气动优化措施,通过节段模型风洞试验研究了PK箱梁在0°、±3°风攻角下的涡振性能,并测试了人行道高度、封闭挑臂底部、栏杆透风率改变、不同倾角抑流板等气动措施对PK箱梁气动稳定性的影响,研究表明:主梁在0°、+3°风攻角下出现强烈的竖向涡激共振,并出现多个竖向涡振区间,同时在高风速下主梁出现了明显的扭转涡振;抬高人行道高度能降低各攻角下主梁的竖弯涡振响应,同时高风速下的扭转涡振得到极大程度的改善;通过封闭栏杆来改变栏杆透风率的研究发现,竖向间隔封闭人行道外侧护栏能破坏涡激气动力在展向的相关性,将主梁涡振峰值响应降低至规范限值的55.8%;0.25 m宽抑流板能有效改善主梁气动稳定性,抑流板倾角变化在20°~75°之间时,其均能完全抑制主梁涡振响应;气流在迎风侧人行道护栏处发生分离,在上表面卷起形成规律的大尺度旋涡,从而造成主梁剧烈的涡激振动,抑流板明显破坏了挑臂附近旋涡的形成,无法向下游发展形成规律的大尺度旋涡,从而能有效抑制主梁涡振。Here,to study vortex induced vibration(VIV)performance and aerodynamic optimization measure of PK box girder with cantilever arm,VIV performance of PK box girder was studied with segmental model wind tunnel tests under 0°and±3°wind attack angles.Effects of aerodynamic measures of footway height,closed cantilever arm bottom,changes in railing ventilation rate and flow suppression plates with different inclination angles on aerodynamic stability of PK box girders were tested.The study showed that main girder has strong vertical vortex-induced resonances under 0°and+3°wind attack angles,multiple vertical VIV intervals appear,meanwhile main girder has obvious torsional VIV under high wind speeds;lifting footway height can reduce vertical bending VIV responses of main girder under various angles of attack,meanwhile main girder torsional VIV responses under high wind speeds are greatly improved;vertical interval enclosed footway outer guardrail can destroy the correlation of vortex-induced aerodynamic forces in spanwise direction to reduce main girder peak VIV response to 55.8%of the specification limit;0.25 m wide flow suppression plate can effectively improve aerodynamic stability of main girder,when inclination angle of flow suppression plate varies within the range of 20°-75°,it can completely suppress main girder VIV response;airflow separates at windward side of footway guardrail to curl up on upper surface,form regular large-scale vortices,and cause severe VIV of main girder,while flow suppression plate can obviously damage formation of vortices near cantilever arm and vortices are unable to develop downstream and become regular large-scale ones,so main girder VIV can effectively be suppressed.

关 键 词：PK箱梁 风洞试验 涡振性能 气动措施 

分 类 号：U441.3[建筑科学—桥梁与隧道工程]