Health Monitoring And Condition Assessment For Stay Cables On Cable-stayed Bridge

With bridge structural heath monitoring system, the bridge working status can be monitored and identified, which will ensure safe operation and provide science basis for the management and maintenance. Cables of stayed-cable bridge are the main load-bearing components, its damage have negative impacts on the security, integrity and dynamic and static characteristics of the bridge. Therefore, it is very important for safe operation to accurately assess the working status of stay cables by heath monitoring system.In the paper, on the background of Guangdong Jiujiang Bridge, a heath monitoring system has been established and heath monitoring and condition assessment have been researched. The main contents are as follow:(1) Establishment of the heath monitoring system. This system contains sensor subsystem, data acquisition and transmission subsystem, data process and control subsystem and condition assessment subsystem. Heath Monitoring System Software has been developed and real-time online automate monitoring have been realized.(2) Analysis and process of monitoring data. The change characteristics of the environmental temperature and humidity loads, the stress of the beam, and cable force and the correlation between temperature and cable force are analyzed. As a result, the change lows of the force have been learned, which provides science basis for condition assessment.(3) Research on alarming system. The design, composition and method of implementation of the monitoring system are researched. It consists of two parts: local alarming subsystem and global alarming subsystem. It can realize the long-term cumulative damage alarming and sudden damage alarming.(4) Condition assessment based on novelty detection technique. According to part of the cable forces and temperatures measured by the monitoring system, the two stage neural network model based on novelty detection technique, witch consists of condition alarming and damage location, was established to assess condition of all cables. The neural network model is completely trained by the measured data, making the method with good applicability. The Jiujiang Bridge Condition Assessment Software was developed, which has applied successfully to Jiujiang Bridge and achieved desired results.