考虑减振装置弹簧刚度的斜拉索等效索长及索力测量

摘要

为了提高对安装减振装置斜拉索索力的测试精度,提出计算等效索长的铰接等代法.基于索力振动频率法所采用的弦振动理论,考虑减振装置弹簧刚度对拉索边界条件的影响,着重研究减振装置弹簧刚度与等效索长的关系,提出考虑弹簧刚度影响的二次等效索长修正公式.结合实测索力及通用有限元软件ANSYS关于振动索力的数值模拟结果,验证了该方法的正确性及适用性.结果表明:等效索长是影响索力测量精度的关键参数之一；随着减振装置安装状态的不同,拉索的索力及基频均有一定程度的改变；该方法可以有效提高斜拉桥索力的测量精度,对短索更具工程实用价值.所提出的方法可用于斜拉桥的施工阶段及成桥阶段的索力控制.%To improve measure precision on force of stayed-cable with damping device, equivalent hinge method (EHM) is proposed for calculating equivalent length. Based on string vibration theory used by vibration frequency method for measuring cable-force, impact of spring stiffness of damping device upon boundary condition of stayed-cable is considered. The relationship between spring stiffness and equivalent length is seriously considered. Taking the impact into account, a modified formula is put forward for calculating the secondary equivalent length of cable. After comparing the collected data of cable-force and the numerical results of universal finite element software ANSYS to simulate vibrating cable, correctness and applicability of the method are verified. The results show that equivalent length is one of the key parameters which can affect the precision of measuring cable-force ; when installation situation of damping device is different, both force and fundamental frequency of cable are changed to a certain degree; the precision of measuring cable-force is improved by the proposed method effectively; the suggested method is more practicable for shorter cable. It is argued that the method can be applied for controlling cable-forces of cable-stayed bridge at construction stage or finished stage.