Research On Safety Prognosis Method Of Concrete Cable-Stayed Bridge Based On Structural Health Monitoring

Bridge structural health monitoring has become one of the important means for bridge condition monitoring and safety assessment. Based on structural health monitoring system of Huaian Bridge in Changshen Expressway, safety assessment, safety alerting and safety prognosis method for prestressed concrete cable-stayed bridge will be established in this study. The main work is as follow:1. According to structural characteristics of Huaian Bridge, structural health monitoring system for Huaian Bridge is designed and implemented, and the structural health monitoring data are analyzed.2. Finite element model of Huaian Bridge is updated based on ambient vibration testing results, and the baseline finite element model of Huaian Bridge which reflects actual condition is established. Then, the static and dynamic calculation is conducted to create threshold of safety assessment and alerting.3. Based on the uncertain analytic hierarchy process (AHP), a group of judge, set-valued statistics principle, method of variable weight synthesis theory and entropy theory, comprehensive safety assessment method of Huaian Bridge is established and applied for operating condition.4. Safety alerting index system of Huaian Bridge is established by combination of the baseline finite element model, SVM model and the measured data which is based on Huaian Bridge health monitoring system.5. Safety prognosis dynamic model of Huaian Bridge is built by using the method of mixed Gaussian particle filter(MGPF) and the combination of the improved neural network model.The main conclusion is as follow:1. Based on the baseline finite element model of Huaian Bridge and related codes, structural level limit of safety assessment and threshold of safety alerting for Huaian Bridge are established. And real-time monitoring items that there are lack of specification in current codes are supplemented.2. Considering the fuzziness and uncertainty in the process of assessment, structural comprehensive safety assessment method for Huaian Bridge is established. Integrated safety assessment score of nearly six months is 84.0 points, which suggests that the recent safety situation of Huaian Bridge is in the second level.3. Structural safety alerting system of Huaian Bridge including blue alert, yellow alert and red alert is proposed. The processing results of six months monitoring data show that few data are beyond blue alarming threshold and no data is beyond the threshold of yellow or red alarming which indicates Huaian Bridge is in good condition recently.4. Combining the methods of safety assessment and safety alerting, the method of safety prognosis for Huaian Bridge is established with dynamic model parameters which are built by Gaussian mixture particle filter. The results show that the trend of the predicted and the measured values are almost the same, and the predicted results are in good agreement with the measured results. The prognosis method can be further used for the safety prognosis of the large span cable-stayed bridge.