Key Technology of Structural Health Monitoring of Short and Medium Span Bridges
Short and medium span bridges account for nearly 90％of the total number of bridges in China and are now deteriorating due to aging.Therefore,it is becoming an important social concern to develop health monitoring systems for short and medium span bridges.In the paper,based on the analysis of the factors affecting the safety and durability of short and medium span bridges,such as superstructure type,the proportion of live load,the action time of live load,the mid-span dynamic deflection is determined as the key index to monitor short and medium span bridges,and the requirements of sampling frequency and accuracy are put forward.Based on millimeter-wave radar technology,a pilot application of dynamic deflection monitoring is carried out for a short and medium span bridge that in-service.The mean filter algorithm is used to separate live load deflection from temperature deflection,and a hierarchical alarm threshold setting scheme is determined based on monitoring statistics.Through the pilot monitoring cases,it shows that the dynamic deflection monitoring technology has significant application advantages for short and medium span bridges.
structural health monitoringshort and medium span bridgesdynamic deflectionradar rangingalarm threshold
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