基于曲率模态面积差方比的桥梁结构损伤识别  

Identifying Damage of Bridge Structure Based on Curvature Mode Area Difference Square Ratio

作　　者：吴桐 唐亮[1] 周志祥 WU Tong;TANG Liang;ZHOU Zhi-xiang(State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University,Chongqing 400074,China;School of Civil and Transportation Engineering,Shenzhen University,Shenzhen Guangdong 518060,China)

机构地区：[1]重庆交通大学省部共建山区桥梁及隧道工程国家重点实验室,重庆400074 [2]深圳大学土木与交通工程学院,广东深圳518060

出　　处：《公路交通科技》2021年第11期59-67,共9页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(51708068,51778094)。

摘　　要：为了利用桥梁结构的振动信息对桥梁关键部位进行损伤识别,从而对结构的安全状况进行评价,通过分析桥梁结构振动特性中的关键动态信息———位移模态、转角模态和曲率模态三者之间的关系,提出了一种利用损伤前后曲率模态面积差方比来识别结构局部刚度损伤的方法。该方法根据测点数量将损伤前后的曲率模态曲线所围成的面积划分为若干单元,用单元面积的平方与所有单元面积平方和的比值作为损伤定位参数AD,并推导了该参数的计算公式。不同于传统通过对位移模态2阶差分求得曲率模态,参数AD可直接通过位移模态进行一次差分所得的转角模态值直接计算而得。为验证所提出方法的有效性,分别开展了简支梁桥模型和自锚式悬索缩尺模型桥损伤检测试验,通过切割截面模拟简支梁模型桥损伤,通过释放不同吊杆索力模拟悬索桥模型局部刚度损伤,采集模型桥损伤前后的动态响应信号并进行模态分析得到损伤前后的位移模态曲线,再由位移模态经一次差分计算得到转角模态。根据所推导的公式直接计算可得到各单元的AD值,由AD值的分布定位简支梁和悬索桥模型的损伤。计算结果表明:损伤单元的AD值远大于未损伤单元,能够准确定位结构中不同位置和数量的局部刚度损伤。In order to use the vibration information of the bridge structure to indentify the damage of bridge and evaluate the safety status of the structure,by analyzing the key dynamic information in the vibration characteristics of bridge structure(the relationship among displacement mode,rotation angle mode and curvature mode),a method for indentifying the local stiffness damage of the structure by using the ratio of the difference of the curvature modal area before and after the damage to identify the local stiffness of the structure by using the area difference square ratio of the curvature mode before and after damage is proposed.By using this method,the area enclosed by the curvature modal curves before and after damage is divided into several elements according to the number of measuring points.Taking the ratio of the square of each element area to the sum of the squares of all element areas as the damage location parameter AD,and the calculation of this parameter is derived.Different from the traditional method of obtaining the curvature mode through the second-order difference of the displacement mode,the parameter AD can be directly calculated from the rotation angular modal value obtained by first difference of displacement mode.To verify the effectiveness of the proposed method,the damage detection tests of the model of simply supported beam bridge and the scaled model of self-anchored suspension bridge are carried out respectively.The damage of the former model is simulated by the cut section,and the local stiffness damage of the latter model is simulated by releasing the forces of suspenders.The dynamic responses of the model bridges before and after damage are collected,and displacement mode curves before and after damage are obtained by modal analysis.Then,the rotation angle mode is calculated from the displacement mode through first difference calculation.The AD values of each element can be obtained directly according to the derived formula.The damages of the models of simple supported beam bridge and s

关 键 词：桥梁工程 损伤识别 面积差方比 曲率模态 自锚式悬索桥 

分 类 号：TU317[建筑科学—结构工程]