大跨度斜拉桥拉索的参数振动

目的研究水平拉索和斜拉索在端部轴向激励和桥面竖向激励下的参数振动,探讨两种情况下拉索位移响应及索力的变化规律.方法以实际工程拉索为例,首先对水平拉索参数振动的偏微分振动方程进行数值求解,并进行扫频和参数分析;然后利用ANSYS建立了斜拉索在桥面竖向激励下的有限元模型,进行不同匹配频率下的振动响应分析.结果验证了拉索参数振动的发生条件,得到了拉索激励幅值、阻尼比、初始拉力变化对参数振动时拉索位移和索力的影响规律,以及斜拉索在桥面竖向激励下,振幅和瞬态索力的变化规律.结论一旦发生参数振动,拉索的振幅和瞬态索力都会有很大幅度的提高.有效控制拉索振动,减小振幅是至关重要的,瞬态索力也不容忽视;同时,在进行索力监测时,考虑桥面振动的影响是一个有待深入研究的问题.

Study on the Parameter Vibration of the Large-Span Cable - Stayed Bridges

Parameter vibration of horizontal and inclined cable with axial excitation at end and vertical excitation on deck has been investigated.And the displacement response of cable and cable force has been studied in these two situations.First of all,vibration equation of horizontal cable parameter vibration has been mathematically solved and frequency sweep and parameter have been analyzed,based on practical engineering.Then,FEM of inclined cable with vertical excitation on deck has been built with ANSYS program.And vibration response of various matched frequency has been analyzed.the occurrence condition of parameter vibration has been verified.By means of parameter analysis,the effect law of displacement and force of cable during parameter vibration with excitation amplitude,damping ratio,and initial tension change,and variation law of amplitude and transient cable force with vertical excitation on deck have been obtained.investigation results indicated that once parameter vibration occurred amplitude and transient force of cable will increased significantly.It is very important to control the vibration amplitude of cable.And transient cable force can not be ignored.And also,the effect of deck vibration when the cable force has been monitored is a meaningful issue.