Damage Identification of Bridges Based on Wavelet Packet Analysis

During the long-term service of steel-concrete composite beam bridges, the main beam structure is prone to sustain damage of varying severity due to such factors as sustained load effects and gradual degradation of material properties. The accurate identification of these damages and the implementation of timely maintenance measures are of crucial significance for guaranteeing the safe operation of bridges. This category of research not only holds substantial theoretical value but also can offer technical backing for engineering practices, thereby ensuring the long-term dependability of infrastructure facilities. For this reason, investigations into damage identification of bridges are conducted by means of vehicle-bridge coupling vibration analysis and wavelet packet analysis. Firstly, an analysis is carried out on the construction approach for the relative energy of wavelet packets; the relative energy curvature difference of wavelet packets is defined as the damage index (DI). To perform dynamic response analysis of vehicle-bridge coupling, this paper selects the steel-concrete composite beam bridge as the research object. On the basis of the dynamic model describing vehicle-bridge contact, a numerical simulation of the vehicle model is conducted, and a program for analyzing vehicle-bridge coupling vibrations is developed. Dynamic response signals of the bridge before and after the occurrence of damage are acquired by utilizing the finite element model of the bridge in conjunction with the vehicle-bridge coupling vibration program. A range of damage scenarios (including single damage and multiple damages) are established for bridges. The constructed damage index DI is applied to identify damages under these different damage scenarios. The findings indicate that the damage index DI is capable of accurately recognizing various damage conditions.