Finite Element Model Updating Of Bridge And Coupling Vibration Analysis On Wind-Vehicle-Bridge System

The long-span bridge structure is more flexible,and the coupling vibration effect between the vehicle and the bridge is excited by the bridge’s surface roughness.When bridges are located in a robust wind environment,the vehicle is subjected to lateral force and overturning moment under the action of the lateral wind,and the vibration characteristics of the vehicle are significantly changed.The flexible bridge is affected by the fluctuating component of the wind,which also produces buffeting or flutter.The vibration responses of bridges and vehicles are exacerbated by these vibration modes’ superposition and coupling effects.To ensure the safety of the bridge structure and the safety and comfort of the vehicles running on the bridge,it is important to study the prediction of wind velocity in the bridge site area and the dynamic interaction between the vehicles and the bridge under the wind load.In engineering applications,the initial bridge finite element model is usually established based on the engineering drawing,while the actual bridge often suffers from various diseases such as structural damage and material aging after a period of service,resulting in the established finite element model not reflecting the actual state of the bridge.Therefore,before conducting the wind-vehicle-bridge coupling vibration analysis,establishing an accurate and refined finite element model is an important prerequisite to carry out the series of works.In this paper,a thorough and systematic research has been conducted to solve the above problems,and the main work is as follows:(1)The Qingzhou Bridge is taken as the engineering background and the initial finite element model of the bridge is established.The first 5th-order modes are taken as the response value,The elastic model and unit weight of the main beam,bridge deck,and stay cable are selected as the parameters to be modified.The sparrow search algorithm(SSA)is introduced and combined with the response surface method to update the initial finite element model.The calculated values of the modified model are closer to the static and dynamic load test results of the bridge,and the reliability of the method is verified.(2)A wind velocity prediction method combining empirical modal decomposition(EMD),SSA,and a bi-directional long and short-term memory model(Bi LSTM)is proposed.The results of different prediction methods are compared to prove the superiority and prediction accuracy of this method,and it’s applied to predict the wind velocity in the bridge site area of the Qingzhou Bridge to lay the foundation for the subsequent wind load model and verify the accuracy of the wind load model.(3)The updated finite element model of the Qingzhou Bridge is used,and the coupled wind-vehicle-bridge vibration model is established by considering the static wind force,buffet wind force,self-excited wind force acting on the bridge as well as the static wind force,and buffet wind force acting on the vehicle,respectively.The corresponding calculation program was compiled.The dynamic response of the vehicle and bridge to different wind loads,wind velocity,vehicle speed,bridge surface grade,bridge wind attack angle,vehicle load,and combined effect of wind velocity and vehicle speed are comprehensively analyzed,and the riding comfort under different working conditions is further analyzed.