Damage Detection Of Beam Bridge Structure Based On Principal Component Analysis And Grey Relational Analysis

Bridge is one of the important infrastructure in the human society.Generally,the bridge will be damaged caused by various factors in its long term service.If it is not detected and repaired in time,the bridge may collapse,which will destroy people's safety and affect the social and economic development.Therefore,the health monitoring and damage detection of bridge structures are particularly important.In this thesis,according to the influence of the noise,a damage detection method using principal component analysis(PCA)combining with wavelet threshold noise reduction is proposed.In order to solve the problem that a large number of damage detection methods need plenty of sensors,another damage detection method based on grey correlation coefficient using a single sensor is proposed.The main works of this thesis are as follows:1.The research background and significance of bridge health monitoring are systematically introduced,and the current damage detection methods at home and abroad are summarized.According to the difficulties and challenges in SHM,this thesis proposes the methods to reduce the influence of noise and to detect the structural damage with a single sensor2.The vehicle-bridge coupling vibration theory of the vehicle-bridge sestem is introduced.Then a damage detection method based on principal component analysis combining with wavelet denoising method is proposed.This method can reduce the influence of the noise through the wavelet denoising for the measured data with noise.Besides,a single sensor damage detection method based on grey correlation coefficient is proposed to reduce the number of sensor usage.3.The effectiveness of the two damage detection methods proposed in this thesis is verified by numerical simulation of a simply supported beams under a moving loads.The results show that the two methods have good damage localization ability under different working conditions.4.Experimental verification.A simple beam bridge model is employed and the responses of the beam model subjected to a moving vehicle under the damaged and undamaged senarios are measured,which are analyzed with the two damage detection methods proposed in this thesis.The experimental results showed that both methods can effectively locate the damage.The two methods are compared and the advantages and disadvantages.