Research On Safety Early Warning Method Of Operational Bridge Structure Based On Cross-correlation Function Analysis

The structure safety early warning system of operation bridge can monitor its safety performance in real time and timely feedback to the corresponding management department in order to take timely measures.Structural damage identification method is the core of structural safety early warning system,domestic and foreign scholars have carried out extensive research on this subject,and has achieved fruitful results.However,most of the existing research methods are based on a priori numerical simulation and experimental analysis,and there are serious applicability problems and many other different from the experimental and numerical simulation of the difficulties in the application of practical engineering.Therefore,the structural damage identification method of the existing bridge under the random vibration of the environment becomes the practical requirement of the research on the safety problems of the existing bridge structures under the new traffic environment.Based on the monitoring data of bridge structure under random vibration,this paper studies the method of structural safety early warning based on the analysis of structural response cross correlation function.The details are as follows:(1)The theoretical analysis of the cross-correlation function between the responses of structures under different noise is described.The specific method of taking the cross correlation function amplitude vector as the damage identification index is established,and the numerical examples are used to verify the applicability of the method.And the shortcomings of this method in engineering application are analyzed.(2)The processing methods of several mainstream vibration signal are described.The theoretical basis of the vibration signal processing method and the basic principle of denoising based on the wavelet transform are introduced.The key factors influencing wavelet denoising are analyzed,and the advantages and disadvantages of various wavelet denoising methods and engineering practicability are compared by simulation experiment.The optimal wavelet denoising method obtained from the simulation experiment is applied to the real monitoring data of the in-service bridge,which verifies the feasibility and effectiveness of the signal processing under the excitation of the random environment.(3)Introduce the classification of structural safety early warning method.The method of data preprocessing and analysis,determining the reference cross-correlation amplitude vector,and determining and updating the warning threshold are put forward based on the principle of statistics and the principle of amplitude vector of cross-correlation function.And apply these methods to the security monitoring and analysis of the operation of real bridge structure before and after the tyranny of Morandi.The analysis results show that the bridge structure safety early warning method of cross-correlation function analysis based on random vibration can be effectively applied to the structural monitoring of the operation bridge.