Bridge Structure Damage Identification Method Based on Displacement Influence Line and Wavelet Packet Analysis

Based on the principles of displacement influence lines and wavelet packet transform,a bridge structural damage identification method is proposed,which relies on three damage indicators:displacement influence line difference,displacement influence line difference curvature,and wavelet packet relative change rate.Taking a continuous beam as the research subject,the differences in structural damage identification among the three damage indicators at different damage locations and severity levels are analyzed.Furthermore,the impact of structural response types and factors such as bidirectional traffic on the identification results is explored.The analysis results indicate that all three feature indicators can effectively identify structural damage.The curvature of the displacement influence line difference curve has larger extremes at the damage locations compared to the extremes of the displacement influence line difference curve.The RES curve significantly improves the identification performance near the beam’s end,being more sensitive to local damage in bridge structures.The RES curve constructed with displacement as the input parameter exhibits the best comprehensive identification performance.The RES indicator can effectively resist interference from bidirectional traffic in the application of bridge damage identification.