Research On Safety Evaluation Of H Cable-stayed Bridge In Fengtai County Based On Monitoring System

With the continuous development of the transportation industry,the total number of bridges in China has exceeded one million.With the increase of bridge operation time,the problems of bridge safety and disease gradually emerge.In order to ensure the safety and normal operation of bridge structures,the bridge safety monitoring system has been widely used in the daily operation of long-span bridges.Because of its advantages of realtime monitoring,stable work,long-term operation,it provides great convenience for realtime understanding of bridge conditions and bridge management and maintenance decisions.In the operation process of the monitoring system,the selection and application of monitoring parameter types,the rationality of the layout of each monitoring parameter measuring point,and the optimization of the best model to process the monitoring data.so as to make a more accurate and reasonable assessment and judgment of the safety status of the bridge,are the hot spots that scholars have been committed to studying today.This research is based on the bridge structure safety monitoring system.In the early stage,summarized the literature research results of bridge monitoring and safety condition evaluation methods at home and abroad,took the safety condition evaluation methods of cable-stayed bridges as the main research direction,combined with the engineering case of H cable-stayed bridge in Fengtai County,proposed how to accurately evaluate the safety condition of bridges during the operation period,and through the establishment of safety evaluation methods,obtained the safety condition and maintenance suggestions of bridges.Firstly,based on the main diseases of cable-stayed bridge and the design principle of monitoring system,this study elaborates the layout scheme of sensors of monitoring system of Fengtai H cable-stayed bridge.Use Midas Civil finite element analysis software to simulate H cable-stayed bridge,select specific working conditions for finite element analysis,analyze the extreme value of force on each node of the model through the principle of load influence line,and calculate the threshold value of each monitoring point.The statistical extreme value,mean value and relative change rate of each month are analyzed to reflect the distribution and change trend of the annual monitoring values.The monitoring system of H cable-stayed bridge in Fengtai County was rectified and optimized by using the analytic hierarchy process,and the target layer,criterion layer and scheme layer were determined respectively.The evaluation index weight system of H cable-stayed bridge monitoring system was established.The weight of the monitoring parameters of the bridge at all levels was calculated to determine the damage proportion weight of each component of the cable-stayed bridge.The evaluation index with high analysis weight shall be the key observation and maintenance parts of the bridge during the operation period,and provide the main reference for the maintenance decision of the cable-stayed bridge.Establish the steps and procedures of bridge safety condition evaluation method,calculate the evaluation score of monitoring data collected by each monitoring parameter measuring point by using the lowest level index evaluation membership function,and score from the lowest level index to the upper level according to the evaluation index weight system to finally obtain the hierarchical score of the overall bridge structure safety condition.Finally,according to the evaluation results of bridge safety,we should pay more attention to the location changes of measuring points with low rating in the daily bridge management and maintenance,pay attention to their fatigue damage,and take corresponding reinforcement and maintenance measures for the corresponding bridge components according to the bridge evaluation results and in combination with the on-site inspection results,so as to ensure that their structures are comprehensively and reasonably maintained,and ensure the normal operation of the bridge.Figure [26] Table [56] Reference [45]...