某宽幅箱梁悬索桥气动特性节段模型风洞试验

Wind Tunnel Test of Aerodynamic Characteristics of a Wide Box Girder Suspension Bridge

大跨度桥梁由于其结构轻柔,容易出现静力失稳现象及各种形式的风致振动。通过对节段模型风洞静力三分力试验验证了某宽幅闭口箱梁悬索桥没有出现驰振的可能,并对全桥进行了几何非线性静风稳定分析,得到该桥的静风失稳临界风速。通过风洞弹性悬挂节段模型试验,得到了该桥的颤振临界风速。分析了阻尼比对于颤振临界风速的影响,试验结果表明阻尼比对于颤振临界风速影响不大。在风洞中观察到该桥成桥态在+3°、+5°攻角会出现扭转涡激振动,提高阻尼比可以有效降低涡振振幅。

Long-span bridges are prone to various forms of wind-induced vibration due to its soft structure.In this paper,the aerostatic force coefficients by wind tunnel test of a suspension bridge with a wide steel box girderhas been studied.A geometric nonlinear analysis of the entire bridge has been performed to obtain the critical wind speed of aerostatic stability of the bridge.The critical wind speed flutter of the bridge has been obtained through the wind tunnel elastic suspension sectional model test.The influence of the damping ratio on the critical wind speed flutter has been examined.The test results have shown that the damping ratio has little effect on the flutter critical wind speed;It has been observed that the torsional vortex-induced vibration of the bridge in the bridge appears at+3°and+5°attack angles in the wind tunnel.Increasing the damping ratio can effectively reduce the vortex amplitude.