Research On Bridge Damage Identification Method Based On Vehicle Vibration Time History Signal

Structural damage identification is an important part in the field of SHM,but the conventional manual inspection lacks the determined data of the structure health status and quantitative standard.Based on the national natural science foundation of ChinaStudy on obtaining the bridge holographic deformation and structure state deduction based on image contour overlap analysis(51778094)and the WWWQ-Watching,Hearing,Asking,and Touching bridge safety monitoring technology hosted by the tutor,a damage detection method is proposed in this paper to determine the damage of bridge structure by using the dynamic response signals of the passing-by vehicles collected by onboard vibration sensors based on the branch technical route of Touching,which can provide technical support for the implementation of WWWQ bridge safety monitoring technology.The main research contents are as follows:1)The VBI theory model is established,and the components of vehicle response are qualitatively analyzed theoretically.The analytical expression of the acceleration response of the vehicle is derived in detail,and the correctness of the analytical derivation of the vehicle acceleration response is verified by a numerical example.The theoretical analysis results show that the " damage components " related to structural damage will be contained in the acceleration response of the passing-by vehicles when the structure is damaged,which can be used for structural damage detection.2)A structural damage identification method based on Multi-scale Wavelet Energy is proposed,and the damage discriminant factor DI is defined as the difference of MSWE between the initial state and the unknown state.The effectiveness of the proposed method is discussed by establishing a VBI numerical simulation model.The results show that the proposed method can effectively identify the single damage and multiple damages of the bridge,the peak of the DI value can reflect the relative degree of structural damage,and the proposed method is insensitive to the general environmental noise.3)The VBI experiment model is constructed in the laboratory,and the vertical acceleration time history signal of the vehicle is collected by the onboard acceleration sensor.The Single-scale Wavelet Decomposition for the structural modal identification method is proposed,and the acceleration response of the vehicle is used to obtaining the modal parameters of the bridge.The test results show that the first three natural frequencies of the structure can be effectively identified by using the vehicle acceleration time-history signal,with the maximum error of-5.82%,and the recognition guarantee rate of the structure mode shape can reach 0.9245.4)The damage simulation of the experimental model is carried out,and the practical application effect of the damage identification method based on MSWE and the damage identification efficiency are discussed.The results show that this method can effectively identify the damage of the model bridge,and the repeated data acquisition and average processing will help to eliminate the influence of random noise and accidental error.This method can reach the second layer of SHM and can provide useful information related to the damage severity.