Prediction of Wind Velocity to Raise Vortex-Induced Vibration through a Road-Rail Bridge with Truss-Shaped Girder
Prediction of Wind Velocity to Raise Vortex-Induced Vibration through a Road-Rail Bridge with Truss-Shaped Girder
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DOI：
10.1155/2018/2829640
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发表时间：
2018-08
影响因子：
1.6
通讯作者：
Seungtaek Oh;S. Seo;Hoyeop Lee;H. Lee
中科院分区：
文献类型：
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作者：
Seungtaek Oh;S. Seo;Hoyeop Lee;H. Lee
桥梁涡激振动（VIV）涉及到流固耦合和桥梁监测系统的维护，在低风速下由于气动失稳会引起疲劳和使用问题。通过直接测量旋涡脱落频率和风速来指示梁的最大位移，对涡激振动进行了广泛的研究。然而，以往的研究大多集中在固定位置安装结构对风速和剥离频率的估计上，没有对不同结构固有频率下提高涡激振动的风速预测进行研究。本文提出了在不同固有频率下，对桁架梁公路桥进行风速预测，以提高其振动振幅的方法。为此，利用共振现象进行了12例不同固有频率的动力风洞试验。因此，通过动力风洞试验，可以合理地预测风速以提高最大均方根位移的涡激振动。在动态风洞试验中，用固有频率代替旋涡脱落频率来预测风速是可行的。最后进行曲线拟合，预测实际桥梁的风速。结果表明，由于截面形状决定的斯特劳哈尔数的特性，可以在任意固有频率下对动风洞试验中发生涡激振动的风速进行适当的预测。
Vortex-induced vibration (VIV) of bridges, related to fluid-structure interaction and maintenance of bridge monitoring system, causes fatigue and serviceability problems due to aerodynamic instability at low wind velocity. Extensive studies on VIV have been performed by directly measuring the vortex shedding frequency and the wind velocity for indicating the largest girder displacement. However, previous studies have not investigated a prediction of wind velocity to raise VIV with a various natural frequency of the structure because most cases have been focused on the estimation of the wind velocity and peeling-off frequency by the mounting structure at the fixed position. In this paper, the method for predicting wind velocity to raise VIV is suggested with various natural frequencies on a road-rail bridge with truss-shaped girder. For this purpose, 12 cases of dynamic wind tunnel test with different natural frequencies are performed by the resonance phenomenon. As a result, it is reasonable to predict wind velocity to raise VIV with maximum RMS displacement due to dynamic wind tunnel tests. Furthermore, it is found that the natural frequency can be used instead of the vortex shedding frequency in order to predict the wind velocity on the dynamic wind tunnel test. Finally, curve fitting is performed to predict the wind velocity of the actual bridge. The result is shown that predicting the wind velocity at which VIV occurs can be appropriately estimated at arbitrary natural frequencies of the dynamic wind tunnel test due to the feature of Strouhal number determined by the shape of the cross section.