廊架对人行刚构桥涡振性能的影响

Effect of corridor frame on vortex-induced vibration performance of pedestrian rigid frame bridge

为研究装饰廊架对桥梁涡振性能的影响,以某带有空间廊架的景观人行桥为工程实例,制作了小、中、大3种廊架尺寸的主梁节段模型,通过节段模型风洞试验,分析廊架对主梁涡振性能的影响;为考虑实桥空间廊架造型尺寸变化对全桥气动特性的影响,通过全桥气弹模型风洞试验,分析均匀流场和紊流场中主梁跨中和1/4跨处的位移响应。结果表明:装饰廊架会明显改变主梁的涡振性能,小廊架和中廊架状态涡振性能较无廊架状态差,而大廊架状态涡振性能明显优于无廊架状态,大廊架状态除在个别工况出现小幅度涡振外,其他工况均无涡振出现;随着廊架尺寸的增大,主梁涡振性能得到改善;主梁迎风侧不同时,涡振响应会有较大差异,迎风侧宽与迎风侧窄相比,无廊架、小廊架和中廊架最大振幅分别减小49.72%、27.57%和23.21%;全桥气弹模型在均匀流场和紊流场试验中均未出现明显的涡振现象,因此安装装饰廊架的桥梁涡振性能明显优于不安装廊架状态。

To study the influence of corridor frame on the vortex-induced vibration performance of bridge,by taking a footbridge with corridor frame as the engineering example,the rigid segment model with three different corridor frame size was made,and the wind tunnel test of corresponding segment model was carried out to analyze the influence of corridor frame on the vortex-induced vibration performance of girder.In order to consider the effect of space frame size variation on the aerodynamic characteristics of the whole bridge,the displacement response of girder at the span and 1/4 span in the uniform and turbulent flow field was analyzed through the wind tunnel test for the aeroelastic model of whole bridge.It revealed that:Corridor frame significantly changes the vortex-induced vibration performance of the bridge,and there is a large amplitude of vortex-induced vibration in the non-corridor frame state.Vortex-induced vibration performance of the small corridor frame and middle corridor frame is worse than that of non-corridor frame,while vortex-induced vibration performance of large corridor frame is better than that of non-corridor frame.Compared with the three different states,the vortex-induced vibration performance improves with the increase of corridor frame size,and except for the small-amplitude vortex-induced vibration in some operating conditions,there is no vortex-induced vibration in other operating conditions for the state of large corridor frame.If the upwind side of beam is different,the vortex-induced vibration response can be different.The maximum amplitude of the non-corridor frame,small corridor frame and middle corridor frame at the wide windward side is reduced by 49.72%,27.57%,and 23.21%,compared with those at the narrow windward side,respectively.Combined with the fact that there is no vortex-induced vibration under the uniform and turbulent flow field in the aeroelastic test of the whole bridge,the space corridor frame overall improves the vortex-induced vibration performance of the bridge.