Research On The Method Of Damage Identification And Evaluation Of Curved Continuous Rigid Frame Bridge Based On Wavelet Analysis

Because of the continuous rigid frame bridge girder and piers are rigidly connected,under vertical load,the negative bending moment ends with unloading effect on positive moment across the main beam,so the cross section can be reduced,and the clearance under the bridge,vision,and the pier beam consolidation,do not need to support the whole bridge together,good seismic performance advantages and is widely used,But after years of operation,often exhibits various damage conditions(with fracture is the most common),therefore,it is necessary to assess the damage location and damage degree of the bridge,to make a scientific and reasonable judgment on the bridge,the bridge maintenance and reinforcement and technical services.Based on the operation years of yunnan dragon bridge(continuous rigid frame)based on the project,for the positioning of the damage location and damage degree evaluation were studied.(1)Refer to the relevant literature,summarize the research status of the bridge structure damage identification and damage assessment at home and abroad.aiming at the existing problem of current research stage,damage identification and evaluation of the wavelet analysis is proposed.(2)By using the finite element software MIDAS to establish the dragon bridge nondestructive and partial damage finite element model,the data in the matlab wavelet analysis,localization damage location through the singular points of wavelet coefficients in the residual plots,It is indicated that wavelet analysis has good applicability on the continuous rigid frame bridge.(3)In order to illustrate the applicability of the wavelet transform in the continuous rigid frame bridge,the damage detection is divided into single damage and multiple injuries in two conditions,and study the similarities and differences between the wavelet variation in single operating condition and two conditions.Found that wavelet transform in shall only injury condition recognition effect is much better than in the trauma conditions,under the same damage degree,the peak value is greater than the side span area to the midspan peak;Under multiple injury conditions,if the extent of the damage is large and the damage is less,there may be a signal covering up and not being recognized.In this paper,the accuracy of damage identification can be improved to some extent by piecing together the condition that can not be accurately identified for low damage of continuous rigid frame bridge.(4)Seeking stability parameters of bridge damage evaluation and application of Lipschitz index to determine the function of the regularity,there is a linear relationship between the apparent study found that Lipschitz index and the extent of the damage,it is only correlated with the degree of injury,is a stable evaluation index.(5)The measured data of the real bridge in the application of wavelet for the continuous wavelet transform,evaluate the damage location and damage degree,given the current actual situation of operation stage of continuous rigid frame bridge,operational stage of scientific and reasonable suggestions are given.