Abstract
Principal component analysis (PCA)-based method is popular for detecting the damage of bridges under varying environmental temperatures. However, this method deletes some information when the damage features are projected in the direction of nonprincipal components; thus, the effectiveness of PCA-based methods will decrease if the deleted information is related to bridge damage. To address this issue, a hybrid method is proposed to detect the damage of bridges under environmental temperature changes. On one side, the PCA-based method is applied to deal with the nonprincipal components; on the other side, the Gaussian mixture method (GMM) is used to classify all the principal components into different clusters, and then the novel detection method is implemented to detect bridge damage for each cluster. In this way, all the damage feature information is saved and used to detect bridge damage. The numerical example and example of an actual bridge show that the proposed hybrid method is effective in detecting bridge damage under environmental temperature changes. The GMM is effective for classifying the natural monitoring frequency data of actual bridges, and the relationship between the natural frequencies of actual bridges and the environmental temperature is not always linear.
Highlights
Using the advanced sensing technique, structural health monitoring (SHM) technique can diagnose the structural damage and assess the structural safety of bridges by using the different types of structural response [1,2,3,4]
The similar research results were obtained in references [11,12], and the results showed that the changing of natural frequencies caused by the structural damage of the Z24 Bridge in Switzerland was less than the variation of the natural frequencies induced by the environmental temperature changes
A hybrid method is proposed to detect the damage of bridges under environmental temperature changes
Summary
Using the advanced sensing technique, structural health monitoring (SHM) technique can diagnose the structural damage and assess the structural safety of bridges by using the different types of structural response [1,2,3,4]. The PCA-based method is commonly applied to mitigate the nonprincipal component θ 2 are obtained by the equation influence of fluctuating environmental temperatures on the results of damage detection of bridges. The Mahalanobis distance based on a Gaussian probability distribution is applied to calculate the discriminant metrics of θ2 ; for the damage features projected in the direction of principal component θ1 , a Gaussian probability distribution is not valid because the environmental temperature is nonstationary To address this issue, the GMM is used to classify θ1 into several clusters, and for each cluster, the components of θ1 satisfy the Gaussian probability distribution. The novel detection method based on the Mahalanobis distance can be applied to detect bridge damage
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