基于跑车余振的混凝土梁桥阻尼比估算方法  

Damping Estimation of Concrete Girder Bridge Based on Damped Free Vibration Under Vehicle-Running Experiment

作　　者：王宗林[1] 李伟钊[1] 盛可鉴[1,2] 

机构地区：[1]哈尔滨工业大学交通科学与工程学院,哈尔滨150090 [2]黑龙江工程学院土木与建筑学院,哈尔滨150050

出　　处：《振动．测试与诊断》2012年第3期414-418,514,共5页Journal of Vibration,Measurement & Diagnosis

基　　金：国家自然科学基金资助项目(编号:50678051)

摘　　要：分析了混凝土梁桥跑车余振信号的特点,提出桥梁自由衰减振动分段幅值估算阻尼比的方法,以提高阻尼比的识别精度。该方法通过对结构余振信号分段截取做FFT变换,利用相邻两块数据的幅值求得其阻尼比。仿真分析比较了该方法与传统半功率点法估算结构阻尼比的精度,结果表明该方法在有限衰减数据长度内精度优于传统半功率点法。利用该方法对某混凝土连续刚构桥的跑车余振信号进行阻尼比识别,得到前两阶竖弯频率对应的阻尼比,识别结果稳定,可作为该桥的实际阻尼比。The characteristics of damped free vibration of concrete girder bridge under vehicle-running experiment are investigated.A method for damping estimation of structural damped free vibration by segment spectrum analysis is presented to improve the accuracy of damping identification.Firstly,the damped free vibration signal is intercepted by segmentation.Secondly,the amplitude of adjacent segments after FFT transform is taken to estimate the damping ratio.The accuracy of the present method and the traditional half power point method are compared by simulation.The results show that this method has higher accuracy than the half power point method when the length of the damped free vibration signal is limited.The method is used to estimate the damping ratio of a concrete continuous rigid frame bridge based on damped free vibration under vehicle-running experiment.The first and second order vertical flexural frequencies and damping ratios are got.The results are credible and can be taken as the real damping ratios of the bridge.

关 键 词：梁桥 阻尼比 跑车试验 自由衰减振动 频谱分析 

分 类 号：U441.3[建筑科学—桥梁与隧道工程] U446.3[交通运输工程—道路与铁道工程]