Damage Detection Of Continuous Girder Bridge Based On Vehicle Response

In recent years,in order to ensure the safety of bridge structures,bridge damage detection and health detection have become popular research directions.In the past two decades,bridge damage detection has mostly used the static（dynamic）response of the bridge to identify bridge damage,but there have been problems such as the need to deploy a large number of sensors and the closed bridge during detection.For this reason,the damage detection method of continuous girder bridge based on vehicle response was proposed,and the degree of damage was judged.The main research contents are as follows:（1）Based on the response equation of vehicle-bridge coupling vibration,the finite element analysis and calculation method of vehicle-bridge coupled vibration was established,and the correctness of the algorithm was verified by using previous calculation data.（2）For new Bridges,a damage identification method of continuous girder bridge based on bridge health data was proposed.According to the acceleration response of the vehicle body before and after the bridge damage,the difference of the acceleration response of the vehicle body before and after the bridge damage was transformed by discrete wavelet transform,and the wavelet transform coefficient was processed by the maximum successive approximation approach（ie,the MSAA method）,so that the damage location could be identified accurately.The influence factors,such as vehicle weight,vehicle speed,road surface roughness,different bridge span layout and noise,were analyzed in depth to improve the applicability of the method.（3）For the old bridge without intact condition data,a damage identification method of continuous girder bridge based on excitation difference was proposed.The vehicle system with different counterweights was driven on the current continuous girder bridge for two times successively,and the discrete wavelet transform was applied to the difference of vehicle body acceleration response during the two detections,and the wavelet transform coefficient was processed by the maximum successive approximation approach（ie,the MSAA method）,so that the damage location could be accurately identified.The influence factors,such as vehicle weight,vehicle speed,road surface roughness,different bridge span layout and tractor counterweight,were analyzed to verify the applicability of the method.（4）After determining the damage location,for the proposed two methods of bridge damage identification,the damage degree of judgment method based on health data and the damage degree of judgment method based on the excitation difference were proposed.Based on the bridge deflection and the bridge deflection difference,the method put forward the damage degree indexes D and E,as well as the damage degree functionS_d1（D）andS_e1（E）,could be used to determine the damage degree of the bridge,and the damage degree of judgment error basically met the requirements.The damage degree of judgment method was suitable for continuous girder bridges with different bridge span combinations,and the damage degree of judgment method based on health data had better robustness.