基于应变比的桥梁损伤识别与评估方法

A Method for Bridge Damage Identification and Evaluation Based on Strain Ratio

为了研究如何应用桥梁健康监测数据对桥梁关键部位损伤进行识别,从而对桥梁健康状况进行有效评价,解决桥梁结构监测数据分析利用方面存在的实用性不强的问题,通过在结构的测试断面和基准断面分别布设一定数量的应变传感器,采用桥梁应变影响线理论,建立了一种基于应变比的桥梁损伤识别与评估方法。分析了大量车辆荷载作用下桥梁应变响应监测数据,利用测试断面与基准断面对应部位的应变比推演出结构刚度退化矩阵,再利用封闭交通情况下测试车辆产生的荷载效应准确获得应变比矩阵和刚度退化矩阵。为分析对于开放交通条件下难以获得准确应变比矩阵的问题,利用随机信号分析理论及统计技术分析应变比的概率分布规律,发现在交通荷载作用下,一定监测周期内测试断面自身不发生损伤时其应变比众值基本保持不变,证明可根据应变比分布规律的变化对测试断面进行损伤识别。提出了封闭交通情况下测试断面快速损伤识别及开放交通条件下的损伤识别方法。将这一方法推广应用到桥梁健康监测系统中,以青银线济南黄河大桥为例,对该方法的有效性进行了验证。结果表明,该方法效率高,精度好,通用性强,能够实现封闭交通下桥梁损伤快速精准识别与评估和开放交通状态下桥梁损伤定期在线识别。

In order to study how to use bridge health monitoring data to identify the damage of bridge key parts,so as to evaluate the health of bridge effectively and to solve the problem of poor practicality in the analysis and utilization of bridge structure monitoring data,a method for bridge damage identification and evaluation based on strain ratio is established by placing a number of strain sensors on the test section and the reference section of the structure and using the theory of bridge strain influence line.A large number of monitoring data of the bridge strain response under vehicle loading is analyzed,the structural stiffness degradation matrix is derived by using the strain ratios of the test section and the corresponding part of reference section,and the strain ratio matrix and the stiffness degradation matrix are obtained accurately by using the load effects of the test vehicles under closed traffic condition.To analyze the difficulty of obtaining the accurate strain ratio matrix under open traffic condition,the probability distribution rule of strain ratio is analyzed using the random signal analysis theory and statistical technology.It is found that(1)when the test section itself is not damaged in a certain monitoring period,its strain ratio remains basically unchanged under the action of traffic load,showing that damage identification on the test section can be performed according to the variation of strain ratio distribution.The methods for rapid identifying the damage on test section under closed/open traffic conditions are proposed.The method is popularized and applied to the bridge health monitoring system.Taking the Jinan Yellow River Bridge on Qingdao-Yinchuan Line for example,the effectiveness of the method is verified.The result shows that the method is efficient,accurate and universal,and can realize the rapid and accurate identification and evaluation of bridge damage under closed traffic condition and regular online recognition of bridge damage under open traffic condition.