大跨度铁路桥梁健康状态评估的统计对比诊断方法研究

Study on the Statistical Comparison Diagnostic Method for Health State Evaluation of Long-span Railway Bridges

利用桥梁结构长期健康监测系统获取的大量数据,结合大跨度铁路桥梁的结构受力特点,提出了一套基于静力识别的统计对比诊断桥梁结构整体性能的评估方法。其基本思路是:先根据桥梁结构完好状态下监测系统所采集到的环境变量(包括环境温度、湿度及荷载等)与结构响应变量的大量样本,采用统计分析的方法建立环境变量与结构响应变量之间的函数关系;在诊断和识别桥梁结构是否异常时,将实测环境变量代入以上函数,预测结构的响应量值,并计算出实测响应量与预测响应量的差值,再将这个差值与事先拟定的诊断标准进行比较,判别桥梁结构是否发生异常。这种方法可以综合考虑多种因素对结构响应量的影响,有望实现对桥梁结构健康状态的实时评估。

Making use of the large number of data measured by the long-term health monitoring system of bridge structures and combining with the mechanics characteristics of long-span railway bridge structures, a kind of statistical comparison diagnostic evaluation method is presented in this paper, which can diagnose the entire structure function of a bridge. This evaluation method is based on static identification. The basic thought of this method is as following, firstly, according to the large number of samples acquired by the monitoring system, such as the environment variables （including the ambient temperature, humidity, loads and so on） and the structure response variance, the method of statistics analysis is adopted to establish the function between the environment variables and structure response variables. Secondly, when the health state of a bridge structure is diagnosed and evaluated, the measured environment variables are substituted into the upper function and the structure response data of the structure is predicted. The D-value between the measured response data and the predicted response data is calculated. Finally, the comparison of the calculated D-value and diagnostic standard is completed, and the health state of the bridge structure is identified. This evaluation method may take comprehensive multi-factor influence on the structure response variables into consideration. There is hope of real-time health state evaluation of bridge structures.