基于幅值谱比对滤波的梁式桥实测冲击系数计算方法  

A Calculation Method of Testing Impact Coefficient for Beam Bridges Based on the Amplitude Spectrum Comparison Filtering

作　　者：刘晨光 张连振[1] 高庆飞[1] LIU Chen-guang;ZHANG Lian-zhen;GAO Qing-fei(School of Transportation Science and Engineering,Harbin Institute of Technology,Harbin 150090)

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

出　　处：《科学技术与工程》2020年第4期1645-1650,共6页Science Technology and Engineering

基　　金：吉林省交通厅重点科技项目(20180305)。

摘　　要：针对目前桥梁实测冲击系数计算方法中,结果受检测人员主观判断影响较大、计算假定与实际工况存在偏差等问题,以低通滤波动、静分离法的核心思想为基础,提出了改进的频域幅值谱比对滤波法用于桥梁冲击系数计算中的动、静位移分量分离。该方法针对动位移结果中静态分量受测试条件干扰程度低、冲击系数检测不需要信号实时处理等工程特点,通过比对多条动位移时程曲线的频域幅值谱结果,根据测试曲线频域幅值谱之间的相似性特点,自适应的确定滤波截止频率,有效地解决了传统窗函数低通滤波法截止频率估计困难的问题。数值计算结果证明,此方法可准确地提取出动位移曲线中的静态趋势项,可作为桥梁真实静位移结果的良好近似。同时,此方法受试验车辆行驶速度、桥面平整状况、测试噪声影响较小,具有良好的工程适应性。There are non-negligible defects in the present calculation methods of testing dynamic impact coefficient,such as the effect of inspector’s subjective judgment or the considerable deviation between calculation assumption and practical condition.Therefore,according to the core idea of dynamic-static separation methods that based on low-pass filtering,a novel dynamic-static separation method,which based on the amplitude spectrum comparison filtering,was proposed.The new method took advantage of the engineering characteristics of the field test of dynamic impact coefficient,for instance,the static displacement component is not easy to be affected by the testing condition,and the testing signal does not need to be real-time processed.Thus the method could adaptively seek out the cut-off frequency for low-pass filter,which was difficult to acquire in the design of traditional dynamic-static separation method based on low-pass filtering.The cut-off frequency was calculated according to the similarities among the amplitude spectrums of different dynamic displacement signals that were acquired in the test.The numerical simulation results show that the new method can separate the static trend displacement from the dynamic displacement curve of the bridge.The separated static curve is a good approximation to the real static displacement of the bridge.Furthermore,the separation result is not affected by the testing vehicle speed,bridge pavement condition,and ambient noise.It has good adaptation in engineering application.

关 键 词：桥梁动力检测 梁式桥 冲击系数 低通滤波 傅里叶变换 

分 类 号：U446[建筑科学—桥梁与隧道工程]