Investigation Of State Identification Technique On Cable-Stayed Bridges During Health Monitoring

In the health monitoring of long-span bridges,the adverse changes of the internal force state are the major factor to damage the safe of bridge structures,so, the state identification subsystem is the key part of the health mornitoring system of bridge structures.Referenses will be provided for the assessment of the health and the safe if the changes of the internal force state are analysed in the health monitoring.Based on a cable-stayed bridge with single tower,steel box girder,single cable plane, this thesis investigates the identification technique of the internal force state for the cable-stayed bridge by use of the finite element software ANSYS.Firstly,the general development situation of cable-stayed bridges and health monitoring technology and the related theories are introduced.Then,using ANSYS to optimize cable forces in order to determine the reasonable finished state.And then using the optimization of cable forces and Monte Carlo method to certificate the state identification method based on examples.Finally,the theory and method of state assessment on bridge structures is introduced.The analysis and calculation displays that the internal force state of cable-stayed bridge can be adjusted by adjusting the cable forces,with the restrictive condition of 10% testing noise,the relative error of internal force state identification can be controlled to below the restrictive condition through the reasonable loading and corresponding test position.So,the state identification method which identifies the cable forces by use of displacement is feasible and effective.