Real-time Monitoring System Of Cable Force Of Dongzhou Xiangjiang Bridge Based On Fiber Grating

As the core component of a cable-stayed bridge,the cable tension affects the safety and stability of the bridge structure.The cable force can be used as an important indicator for the health monitoring of bridge structures.During the construction and operation of the bridge,monitoring the cable force through the monitoring system can understand the force status of the cables and grasp the health status of the bridge structure in time.Since modern cable-stayed bridges are mostly dense-cable systems,real-time monitoring of all cable-stayed cables requires a large amount of data collection,large data processing workload,and high monitoring costs.In actual projects,only some representative cable forces can be monitored.Most cables cannot directly monitor their stress conditions through sensors.How to monitor the working condition of the cable of the whole bridge through the monitoring results of the cable force of the partial monitoring cable,so as to ensure the safety of the bridge cable during construction and use,is a key problem that needs to be solved urgently in the project.This study takes the cable force monitoring of the cable stay of Dongzhou Xiangjiang Bridge as the background.Through the cable force monitoring data and the finite element model calculation and analysis,the cable force of the full bridge cable at the completion stage is obtained,and its health status is analyzed and evaluated.It provides reference data for regularly collecting the cable force of the stay cable during the operation phase,and also provides a basis for the overall evaluation of the bridge and the management and maintenance of the cable in the later period.Improve the safety and reliability of the engineering structure.Mainly completed the following work:First,according to the basic principle of fiber grating sensing technology,the project team established a cable monitoring system for the Dongzhou Xiangjiang Bridge,and successfully collected and monitored the cable force during the construction and completion stages of the Dongzhou Xiangjiang Bridge.Secondly,The MIDAS/Civil software was used to establish a finite element model,and the calculated value of the full bridge cable force during the construction phase was compared with the actual measured value to verify the accuracy and stability of the fiber grating cable force monitoring system.In addition,the health status of the sensor cable at the bridge-building stage is evaluated by the monitoring system,and according to the real-time change rule of the cable force,the influencing factors of the cable force at the bridge completion stage are analyzed,and the stability of the cable force at the bridge-building stage is monitored by the inspection system.Thirdly,using MIDAS / Civil software to analyze the sensitivity of the structural parameters of the Dongzhou Xiangjiang Bridge,In view of the structural errors caused by the changes of different parameters,the finite element structural model of the bridge stage is further modified.By comparing the test data of the bridge static load test with the simulation results of the corresponding working conditions,the agreement between the modified finite element model and the actual bridge is checked,so as to verify whether the model cable force can effectively reflect the force situation of the actual cable stay cable.Finally,the influence of temperature on the cable force is calculated by the finite element software.According to the change law of the cable force affected by the temperature,calculate the cable force of the full bridge cable during the completion of the bridge,and verify the health status of the cable of the bridge during the completion of the bridge.