Theoretical Study On The Graded Warning Of The Health Monitoring Of Continuous Rigid Frame Bridge

The past decade has witnessed a wider application of continuous rigid frame bridge,more health monitoring system based on continuous rigid frame bridge and mature hardware technology.However,most of the systems have only installed the necessary monitoring sensors.Their data analysis,early warning and safety evaluation system is incomplete,and the system target of online warning and offline evaluation is not achieved.Because of these technical problems,most of the health monitoring systems do not really fulfill the functions of monitoring,warning and evaluation in the actual operation.Although there are a lot of theoretical research findings on these technical problems,they have not been effectively applied in the system evaluation.Based on the present studies,this paper has done the following research:the monitoring model of the monitoring system is calculated by the least square method based on the construction monitoring and load test under the condition of considering the shear lag.Then,according to the characteristics of the signal,the appropriate wavelet function and different decomposition levels are selected to decompose the monitoring data.then the suitable de-noising method is chosen for the monitoring data of the system.Thus,the system noise,the vehicle load response,the super abnormal value and the structural response related to the bearing capacity are separated.Among all the long-term monitoring data related to load absorption,response induced by temperature forms a large part.Based on the analysis of temperature data,the structural stress caused by the actual temperature is calculated with the finite element software,which provides basic data for further evaluation basing on testing accumulation and trend value.We have put forward a hierarchical early warning model based on the equivalent coefficient of deterioration in the whole process from data processing to safety assessment.The first level online warning could be achieved through the judgment and recognition of outliers.By using the equivalent coefficient of deterioration to determine the bearing capacity of the structure,we can achieve the second level of early warning.We can also base on the second level of early warning to determine whether it is necessary to assess the structure.Taking the four kinds of evaluation methods as top indexes and combining the traditional hierarchical model of bridge structure,the author establishes a hierarchical analysis model on the basis of the research methods and data of this paper.A fter the establishment of the model,the author invites experts to mark the judgment matrix and then get the weight of different factors of different levels.Based on the theory of grade membership and interval arithmetic,the author has established the evaluation model of this paper,thus achieving the last level of early warning.