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涡激振动是大跨度桥梁在低风速下容易发生的一种风致振动,是大跨度桥梁抗风设计中的重要环节。为了有效抑制桥梁的涡激振动,研究了TMD对桥梁涡激振动的控制。建立了桥梁与TMD组成的振动系统的运动方程,在复频率里对运动方程进行求解,推导了振动系统的频率响应函数,给出了TMD参数优化设计的方法。以一大跨度悬索桥为实例,对该悬索桥进行了1∶20的大节段模型涡激振动风洞试验,获取了桥梁的涡激振动气动参数,分析了TMD对桥梁涡激振动的控制。TMD参数优化结果表明:质量比越大,控制率越高,但工程中应综合经济性等因素考虑合适的质量比;TMD质量比一定时,TMD与桥梁的频率比趋近于1附近,相位差趋近于π/2附近,控制率较高;当桥梁主梁高度对TMD行程有限制时,涡振控制效果将受到影响,利用TMD进行桥梁涡激振动控制需结合TMD的行程来综合考虑参数的优化取值;就本桥而言,当按质量比为1%设计TMD最优参数时,在整个涡振区风速范围内,桥梁的涡激振动都得到了有效的抑制。
Vortex-induced vibration is a kind of wind-induced vibration which is easy to occur in long-span bridges under low wind speed and is an important part of the wind-resistant design of long-span bridges. In order to effectively suppress the vortex-induced vibration of the bridge, the control of the vortex-induced vibration of the bridge by TMD is studied. The equations of motion for a vibration system consisting of a bridge and a TMD are established. The equations of motion are solved at the complex frequency. The frequency response function of the vibration system is deduced. The method to optimize the TMD parameters is given. Taking a long span suspension bridge as an example, a 1: 20 large-section vortex-induced vibration test was carried out on the suspension bridge to obtain the vortex-induced aerodynamic parameters of the bridge. The control of vortex-induced vibration of the bridge by TMD was analyzed. The results of TMD parameter optimization show that the higher the mass ratio is, the higher the control rate is, but the appropriate mass ratio should be considered in the project, such as economy and other factors. When the TMD mass ratio is fixed, the frequency ratio between TMD and bridge approaches 1, The difference tends to be near π / 2 and the control rate is high. When the height of bridge girder has a limitation on the travel of TMD, the control effect of vortex vibration will be affected. Vortex vibration control of bridge using TMD should be combined with the travel of TMD For this bridge, when the optimal parameters of TMD are designed with the mass ratio of 1%, the vortex-induced vibration of the bridge is effectively suppressed in the entire vortex-induced wind speed range.