大跨度铁路斜拉桥索力快速识别方法研究  

Research on Fast Identification Method of Cable Force of Long-span Railway Cable-stayed Bridge

作　　者：曹阳梅 CAO Yangmei(China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China;China Railway Construction Laboratory of Bridge Engineering,Wuhan 430063,China)

机构地区：[1]中铁第四勘察设计院集团有限公司,武汉430063 [2]中国铁建股份有限公司桥梁工程实验室,武汉430063

出　　处：《铁道标准设计》2024年第4期116-122,共7页Railway Standard Design

基　　金：中铁第四勘察设计院集团有限公司科技研究开发计划课题(2022K086,2021K015)。

摘　　要：大跨度铁路桥梁天窗时间有限且上道条件苛刻,如何基于常规监测设备利用简易方式实现大跨度铁路斜拉桥索力高精度识别十分重要。研究提出一种考虑斜拉索抗弯刚度的索力快速识别方法,既可提高索力识别精度又可大量简化运营期索力识别步骤,且不受拉索边界条件和铁路桥梁实际运营状态的限制。研究表明,抗弯刚度是对索力识别精度影响较大的因素之一,通过考虑拉索实际抗弯刚度可以提高索力识别的准确性,基于拉索加速度振动实测数据在拉索简支梁模型基础上建立索频、索力以及抗弯刚度的函数关系,通过数值方法计算实测多阶模态下抗弯刚度—索力连续变化图,再通过多阶模态的交线则可进一步确定拉索的唯一抗弯刚度和索力值,并以某大跨度铁路斜拉桥为依托工程,对方法的有效性进行了验证。结果表明:(1)该方法识别的索力结果相对误差可降低5.22%,换算成绝对索力值可达254.45 kN;(2)在实际应用中识别结果易受到低阶频率干扰,宜采用拉索高阶频率进行识别,建议采用5阶及以上实测频率。In order to deal with the problems of limited skylight time and harsh loading conditions of railway bridges,it is very important to realize high precision identification of cable force of long span railway stayed-cable bridge using common monitoring devices.A fast cable force identification method considering the bending stiffness of the cable is proposed,which can not only improve the identification accuracy of cable force,but also simplifies the steps in cable force identification during operation.The method is not limited by the boundary conditions of the cable and the actual operating state of the railway bridge.Results show that the bending stiffness has great influence on identification accuracy of cable force,which can be improved by considering the actual bending stiffness of cables.Based on the field acceleration data of the cable,the functional relationship between frequency,cable force and bending stiffness is established based on simply supported beam model.The continuous variation diagram of bending stiffness and cable force is plotted by numerical methods,and the unique bending stiffness and cable force value can be further determined by the intersection line of multi-order modes.The effectiveness of the method is verified by a long-span railway cable-stayed bridge.Results show that:(1)The relative error of the cable force identified by this method can be reduced by 5.22%,and the absolute cable force value can reach 254.45 kN;(2)In practical application,the identification results are interfered by low-order frequencies,so it is advisable to use high-order frequencies for identification,and it is recommended to use the measured frequencies of order 5 and above.

关 键 词：大跨度铁路桥梁 斜拉桥 索力识别 抗弯刚度 简支梁模型 实测频率 多阶模态交线 

分 类 号：U24[交通运输工程—道路与铁道工程] U448.27[建筑科学—桥梁与隧道工程] O329[理学—一般力学与力学基础]