悬索斜拉索组合式跨越管桥风致振动分析

应用大型有限元分析软件ANSYS,分别建立了大跨度悬索斜拉索组合式管桥建造时成桥状态和服役20年后运行状态的有限元模型。通过对管桥两种状况下的模态分析,获得管桥前二十阶固有频率和模态振型。在模态分析的基础上,进一步对管桥进行风致振动分析。分析结果表明,风力的等级对管桥疲劳载荷幅值的大小影响不大;管桥在服役20年后,管道和拉索的疲劳载荷幅值低于管道和拉索允许的疲劳强度值,不会引起管桥的疲劳失效,但要高于20年前建造时的疲劳载荷幅值水平。

Wind-induced Vibration Analysis of Suspension and Cable-strayed Combined Pipeline Bridge

Using finite element analysis software ANSYS,a finite element model of the dead state of the suspension and combined cable-strayed pipeline bridge at construction and after 20 years' service is set up. The first twenty order natural frequencies and vibration modes of the two different models are obtained through modal analysis. The wind-induced vibration analysis is studied based on the modal analysis. The results show that the difference of the fatigue load amplitudes caused by different wind-force is not too big. After serving for 20 years, fatigue load amplitudes of the pipeline and the cable are lower than the allowable fatigue strength. So the wind-induced vibration cannot induce any fatigue failure to the pipeline bridge. But the fatigue load amplitude of pipeline bridge after 20 years is higher than that at construction. Therefore, periodic inspection of the bridge is needed for preventing the fatigue failure of the pipeline bridge.