Time-domain Methods For Identification Of Bridge Damage Based On Vehicle-bridge Coupling System

With the rapid development of national transportation industry,infrastructure construction has played an important role,and bridge is an indispensable part.With the continuous increase of vehicle load,the bridges will be damaged to varying degrees.The accumulation of damage will bring hidden danger to structural safety and normal operation.In this paper,vehicle-bridge coupling system is taken as the research object,that is,the normal operational state of the bridge.And the identification methods of structural physical parameters,structural damage and interaction force are proposed.The specific research contents are as follows:(1)The vehicle-bridge coupling time-varying system is analyzed.Based on the sensitivity of bridge response to the change of element stiffness,the damage of bridge structure is identified.The regularization method is introduced to improve the ill posed of solving the inverse problem.Through the numerical simulation analysis,it is verified that the method can identify the damage location and degree better.(2)Based on the unscented Kalman filter algorithm,the physical parameters of the structure are extended to the state variables to identify the elastic modulus of the structure and the damage degree of each element,and the pseudo measurement iterate in the time step,so that the damage factor can converge to the stable value faster.Taking the vehicle subsystem as the research object,and the vehicle bridge interactive force is directly put into the state quantity for recognition.The recognition method is simple and accurate.(3)Based on prestressed concrete bridge with corrugated steel webs,the solid and spatial beam finite element model are established respectively,and the mechanical characteristics are analyzed by numerical simulation.Based on the vehicle-bridge coupling analysis,the sensitivity algorithm is used for off-line identification of structural damage,and UKF algorithm is used for on-line identification of structural parameters,structural damage and vehicle bridge coupling force.