ResearchonHealthMonitoringandEvaluation System Of Wujiang Second Bridge

With the light and soft trends of the design and the complexity trends of the form and the function of the long-span bridge,the safe operation of the bridge structure have became the important question which influenced the national economy and livelihood of the masses.For the features such as the huge investment and long life and the deterioration result from high environmental impact and bearing dynamic load long time,it is imminent to do the condition evaluation and the health monitoring of bridge.Relying on the characteristics of the wujiang second bridge,and refer to the health monitoring and evaluation system which have been built to other bridges,the health monitoring and evaluation system fit for the wujiang second bridge is built. The condition assessment to the operation stage of the bridge with the technology of the real-time health monitoring is achieved.The primary content is as follows.①Basing on the research of bridge assessment at home and abroad,and based on the analytic hierarchy process principle of variable weights,the pattern of hierarchical relations of the health monitoring and assessment indicators system of wujiang second bridge is built and the composite assessment method fit for the operation stage of bridge and the initial weight of the monitoring indicators are proposed.②The static and dynamic characteristics of structure are mastered with the finite element analysis ,so the vulnerable parts of the structure is found,which provides the guidelines for the rational layout of sensors .The basic range of sensor and the threshold of the monitoring indicators are fixed.③The monitoring program of condition evaluation parameters is developed.and relying on the principles of scientific and practical and complete and open and better relibility,the sensor subsystem such as the kind and the location and amount of sensors are established.The real-time online monitoring of bridge is achieved.④The real-time monitoring data is pretreated with the method of statistical analysis to eliminate the temperature influence.⑤The time-frequency of vibration signal is implemented with flourier transform.Basing on the peak method,the cable stress can be get throughing identificate the cable-stayed Base band with the power spectrum difference method and the cestrum analysis. ⑥The statistical model analys of real-time monitoring datas are carry out,and the short-term model and long-time model of monitoring indicators are established,and the effect of external factors to the changes of monitoring indicators is found.⑦The condition assessment of monitoring project is carry out and the service status of monitoring indicators is get.The algorithm program is prepared with C++ language ,and the comprehensive assessment system software of wujiang second bridge health monitoring is developed initially.The research in this paper provides the practical and efficient solutions for the construction of the health monitoring and the state assessment system of wujiang second bridge and it also provides the reference for the establishment of state assessment system of the same type bridge.