Application Of Wavelet Transform To Damage Identification Of Simple Supported Beam Bridge And Continuous Girder Bridge

Prestressed concrete beam bridge and continuous girder bridge are widely used in municipal highway bridges in China,due to the requirement of increasing the transportation capacity,these bridges are often overloaded and far beyond its design carrying capacity.in addition,the bridge structure has been serving many years,a significant reduction in the mechanical properties.During the daily use of a bridge,bridge structure damage becomes a problem in transportation development.Therefore,it is necessary to identify the damage of bridge structure and make some effective reinforcement measures to avoid safety accident.Bridge operating for many years with injuries,bridge structural damage caused modal parameters change which affect the mechanical response,in order to find detection of structural damage,we should know the relationship between the mechanical response and modal parameters.the change of the modal parameters as structural damage characteristics.In recent years,wavelet transform as a mathematical theory and methods in the scientific community causing more and more concern and attention in all fields.Wavelet transform in bridge structure damage identification has become a hot research in civil engineering.in this article by the following main tasks:1.elaborated this article research background and significance,the bridge structure damage identification of common method and wavelet theory in the application of the bridge structure damage detection.2.The system introduces the theory of wavelet analysis,including a summary of the historical background and wavelet theory Wavelet theory generated.3.elaborated based on wavelet abnormality signal detection and recognitionprinciple,wavelet transform modulus maxima and singularity index calculation determined,and describes the principles and project selection wavelet function of several commonly used wavelets.4.The beam damage mechanics model is presented in this paper,use finite element software to simulate a simply supported beam,the damage of a simply supported beam is different.when beam damage mechanics model is analyszed,which obtains each order displacement modal vibration mode,it means that obtains order curvature mode by center interpolation method,each order curvature mode as a signal,to choose bior6.8 in Matlab wavelet toolbox to analyze the signal,the result shows wavelet transform coefficients in the multi-scale and regard them as the damage index.on the basis of 3 unit,use anomaly signal detection and identification principle to calculate the Lipschitz index which makes it as an important index to measure the severity of structural damage.5.Continuous girder bridge damage identification,use finite element software simulation for a base variable cross-section girder bridge,using the proposed method of determining the continuous girder bridge damage location and extent of the damage.6.The results of this study are summarized and make a conclusion and prospect.