摘要
随着我国高速铁路的建设发展,一种新型的扁平箱梁外形被广泛应用于大跨度铁路桥梁。为研究该类型梁桥的抗风性能,以某大跨度无风嘴扁平箱梁桥为研究背景,通过节段模型测振、测压试验和流场显示试验,研究该类型主梁在施工、成桥阶段的涡振性能以及风嘴、导流板的抑振效果。研究结果表明:在单悬臂状态和成桥阶段,在3个来流攻角(α=-3°、0°、+3°)下均发生了竖弯涡振;该类型箱梁前缘流动分离呈现出类似矩形体的分布状态;在施工阶段以及成桥阶段,该结构在涡振状态下会形成规则的卡门涡街;加装风嘴,单悬臂状态各个攻角以及成桥阶段+3°攻角下的涡振均被完全抑制,结构上缘的负压绝对值和风压脉动极大值明显减小;对于成桥阶段-3°和0°攻角下的涡振没有抑制效果,风嘴无法减小梁体上缘的风压脉动极大值;加装导流板,在施工阶段,单悬臂状态-3°攻角下的涡振完全消失,+3°攻角下的涡振减小12.3%,对于0°攻角的涡振导流板没有抑制效果;在成桥阶段,-3°攻角下的涡振减小66.4%,0°攻角下的涡振减小58.9%,+3°攻角下的涡振减小57.2%;导流板无法减小施工阶段以及成桥阶段结构上缘的负压绝对值,但可以减小下缘的风压脉动极大值;风嘴显著减小了前缘的流动分离规模,结构上缘无法形成大规模的分离泡,抑制了尾流旋涡脱落的形成;导流板抑制了结构下缘大规模流动分离的形成,从而抑制了尾流的规则卡门涡脱。
With the development of high-speed railway in China,a new shape of flat box girder is widely used in long-span railway bridges.In order to study the wind resistance performance of this type of girder bridge,a large-span flat box girder bridge without wind fairings was taken as the research background.Through section model vibration test,pressure measurement test and flow visualization test,the VIV performance of this type of main girder during construction and bridge completion stage,the vibration suppression mechanism and effect of wind fairings and guide vanes were studied.The results show that the vertical bending vortex-induced vibration occurs at the three inflow angles(α=−3°,0°,+3°)at the maximum single cantilever state in the construction stage and the bridge completion stage.The flow separation of the front edge of this type of box girder presents a distribution similar to that of a rectangular body.The results of flow visualization test confirm that the structure forms a regular Karman vortex street in the vortex vibration state during the construction stage and the bridge completion stage.When the wind fairings are installed,the vortex vibration at each angle of attack of the maximum single cantilever in the construction stage and at+3°angle of attack in the bridge completion stage are completely suppressed,the absolute value of negative pressure and the maximum value of fluctuating pressure at the upper edge decrease obviously.The vortex vibration at−3°and 0°angle of attack in the bridge completion stage are not suppressed and maximum of the fluctuating pressure in the upper region cannot be reduced.When the guide vanes are installed,the vortex vibration of the maximum single cantilever at−3°angle of attack completely disappears,and the vortex vibration at+3°angle of attack is reduced by 12.3%,which has no inhibition effect on the vortex vibration at 0°.In the bridge completion stage,the vortex vibration decreases by 66.4%at−3°angle of attack,58.9%at 0°angle of attack and 57.2%at+3°angle of attack.The guide vanes can not reduce the absolute value of negative pressure at the upper edge of the structure during construction and completion,but can reduce the maximum of fluctuating pressure at the lower edge.The flow visualization tests of the two vibration suppression measures reveal the mechanism of the vibration suppression,the wind fairings significantly reduce the flow separation scale at the leading edge,and the large scale separation bubble cannot form at the upper edge of the structure,which inhibits the formation of wake vortex shedding.The guide vanes inhibits the formation of large-scale flow separation at the lower edge of the structure,and inhibits the regular Karman vortex of the wake.
作者
张艺
李欢
魏高翔
何旭辉
谢祖育
ZHANG Yi;LI Huan;WEI Gaoxiang;HE Xuhui;XIE Zuyu(School of Civil Engineering,Central South University,Changsha 410075,China;High Speed Railway Construction Technology Engineering Research Center,Central South University,Changsha 410075,China)
出处
《中南大学学报(自然科学版)》
北大核心
2025年第2期560-574,共15页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(51925808,52208514,52327810)
湖南省自然科学基金资助项目(2024JJ4063)。
关键词
扁平箱梁
涡激振动
抑振措施
风洞试验
flat box girder
vortex-induced vibration
vibration suppression measures
wind tunnel test
