Damage Detection Of Bridge Structures Based On The Discrete Wavelet Transform

Bridge structures are crucial in transportation. The damage detection technique of bridge structures is a research hotspot, and it is important for theory and application. This paper is based on previous research. It is about the bridge structure damage detection method based on the discrete wavelet transform. The main work includes:Firstly, establishing the equations of vehicle-bridge coupled system with the employment of D'Alembert principle, and solving the problem with Matlab based on Newmark-? principal. Using the WPT to analysis the displacement response of the damaged bridge under a passing vehical. Proposing the displacement energy curvature index to detect the damage. The numerical simulation validated the index to be effect.Secondly, the modal response of damaged bridge is extracted by the discrete wavelet transform. Comparing the damage sensitivity of the vertical acceleration, slope response and strain response. Proposing a combined response which physical meaning is strain. It is combined by three adjacent vertical acceleration response based on the curvature formula; Presenting a damage index corresponding to a area of structure; Using D-S evidence theory to improve the effect of the damge index. The effectiveness of the damage index is validated by numerical simulation and expriment.The last, proposing a new damage detection method based on the wavelet packet transform. It judged the location of damge through add up the times when the WP energy difference obtain the maximum value.