桥梁结构合成功率谱模态频率识别方法的研究  

Modal Frequency Identification Method for Bridge Structures based on Synthetic Power Spectrum

作　　者：刘兴旺 赵大成 陈斌 LIU Xing-wang;ZHAO Da-cheng;CHEN Bin(China Railway Bridge&.Tunnel Technologies Co.Ltd,Nanjing 210061,China;School of Civil Engineering,Southeast University,Nanjing 211102,China)

机构地区：[1]中铁桥隧技术有限公司,南京市210061 [2]东南大学土木工程学院,南京市211102

出　　处：《公路》2025年第2期99-104,共6页Highway

基　　金：国家重点研发计划资助项目,项目编号2016YFC0802202;江苏省科学技术厅项目,项目编号BE2018049。

摘　　要：针对桥梁结构频域分解法单测点振动数据模态频率识别不全,以及某一阶次模态频率峰值较大导致其他阶次模态频率难以识别的问题,以某公铁两用斜拉桥为背景,提出了一种合成功率谱模态频率识别方法。首先将多测点振动数据进行预处理,计算各测点功率谱并进行目标频域区间特征提取;然后将目标频域区间功率谱归一化后在对应频率进行叠加;最后基于归一化后合成功率谱进行模态频率识别,并采用有限元及荷载试验结果对合成功率谱法分析结果进行校验。研究表明,在列车充分激振情况下,主梁各阶模态频率峰值较大,模态频率更加容易识别;单测点振动数据功率谱由于测点位置、振动方向、激振程度的差异,往往只能识别对应能量较高阶次的模态频率,难以全面识别及分析其他阶次主梁振动模态频率;多测点合成功率谱可高效、清晰识别主梁的各阶模态频率,实测结果与有限元分析、荷载试验结果基本吻合,结构各阶模态频率在小范围波动,无较大变化,大桥整体刚度稳定。A synthetic power spectral modal frequency identification method is proposed to address the issue of incomplete modal frequency identification of single measurement point vibration data using frequency domain decomposition method and the difficulty in identifying other modal frequencies due to the large peak value of a certain order modal frequency relying on a road-rail cable-stayed bridge.Firstly,the vibration data from multiple measurement points are pre-processed,the power spectra of each measurement point is calculated,and the features of the target frequency domain interval are extracted.Then,the power spectra of the target frequency domain interval are normalized and stacked at the corresponding frequency.Finally,based on the normalized synthetic power spectrum,modal frequency identification is performed.The analysis results of the synthetic power spectrum are verified by finite element method and load test results.Research has shown that:(1)when the train is fully excited,the peak frequencies of each mode of the main beam are larger,making it easier to identify.(2)The power spectrum of vibration data of a single measuring point can only identify the mode frequency corresponding to the higher order of energy because of the difference in the position of the measuring point,the direction of vibration and the degree of excitation,and it is difficult to fully identify and analyze the vibration mode frequency of other orders of main beam.(3)The measured results are basically consistent with the finite element analysis and load test results.The modal frequencies of each order of the structure fluctuate in a small range without great changes,and the overall stiffness of the bridge is stable.

关 键 词：桥梁结构 健康监测 模态频率 多测点 合成功率谱 识别方法 

分 类 号：U446.3[建筑科学—桥梁与隧道工程] U441.5[交通运输工程—道路与铁道工程]