带挑臂箱梁涡振气动控制试验

Experimental study on aerodynamic control of the vortex induced vibrations of a box girder with projecting slab

摘要:

为尝试一种有效控制带挑臂箱梁涡振的气动措施,以某叠合箱梁斜拉桥为背景,在同济大学TJ-1边界层风洞进行了1∶50缩尺模型10个工况的对比试验,研究移动检修轨道、增设不同形式的导流板和扰流板等气动措施的抑振效果.结果表明:带挑臂箱梁涡振振幅随着风攻角增大而增大,涡振性能对风攻角比较敏感;导流板可能会增大带挑臂箱梁涡振振幅,导流板的夹角和水平板的宽度是影响抑振效果的关键因素,夹角越大,水平板越宽,抑振效果越好;在设有导流板的情况下,检修轨道对带挑臂箱梁涡振性能没有影响,移动检修轨道没有抑振效果;扰流板对带挑臂箱梁抑振效果明显,在一定范围内扰流板越宽抑振效果越明显,而且扰流板对涡振的控制效果同风攻角有密切关系.

Abstract:

To seek an effective aerodynamic measure to control the vortex induced vibrations(VIV) of a box girder with projecting slab(BGPS),VIV of a 1∶50 scale sectional model with 10 cases were tested in TJ-1wind tunnel based on a cable-stayed bridge with composite box girder.The aerodynamic measures whose mitigation efficiencies were studied included moving the rails of tool car,installing guide vanes with different forms and installing spoilers with different forms.The research results show that VIV amplitudes of BGPS increase with the increasing of wind attack angle,so VIV performance is sensitive to wind attack angle.As for the guide vanes,they may raise VIV amplitude of BGPS,and the included angle and the width of horizontal board are key factors to affect mitigation efficiency of them,concretely,the bigger the included angle is and the wider the horizontal board is,the better the mitigation efficiency is.After the guide vanes are installed on BGPS,the rails of tool car have little effect on VIV performance of BGPS,so the mitigation efficiency of moving the rails of tool car is negligible.As for the spoilers,they can control VIV of BGPS efficiently,and the wider the spoilers are,the better the mitigation efficiency is,but the mitigation efficiency of the spoilers is correlative to wind attack angle closely.