闭口钢箱梁悬索桥涡振多尺度模型风洞试验

Multi-scale Model Tests of Vortex-induced Vibration of a Suspension Bridge with Closed Steel Box Girders

闭口钢箱梁悬索桥涡振对行车安全、结构耐久和行人舒适度等十分不利。模型风洞试验是研究悬索桥涡振的主要手段。由于涡振对断面气动外形、结构阻尼和雷诺数较为敏感,节段模型和全桥模型涡振试验中都存在缩尺效应。基于闭口钢箱梁悬索桥1∶122全桥气弹模型、1∶60小尺度节段模型和1∶20大尺度节段模型等三组风洞试验发现模型试验中涡振的尺度效应表现为尺寸增大后涡振风速锁定区间变窄并提前但振幅降低。全桥模型试验主缆涡激力激发了加劲梁桥塔和主缆三者高风速涡振现象。

The vortex-induced vibration(VIV)of closed steel box girder suspension bridgesis harmful to traffic safety,structural durability and pedestrian comfort.Model wind tunnel test is main method to study of VIV.Since VIV is sensitive to aerodynamic geometry,damping and Reynolds number of the section,the scale effects are significant in sectional and full-brmodel wind tunnel testing.3 groups of wind tunnel tests were performed for the 1∶122 full-bridge aeroelastic model,1∶60 small-scale sectional model and 1∶20 large-scale sectional model of a suspension bridge,where the scale effects in VIV presented as the decreasing of critical VIV wind speed and shortening of“lock-in”interval,together with a reduction of VIV amplitude.In the aeroelastic tests,a coupling VIV of girders,cables and towers was observed at a higher wind speed,which was exited by the VIV of cables.