Experimental investigation of damage identification for continuous railway bridges

摘要

Considering the issue of misjudgment in railway bridge damage identification,a method combining the step-by-step damage detection method with the statistical pattern recognition is proposed to detect the structural damage of a railway continuous girder bridge.The whole process of damage identification is divided into three identification substeps,namely,damage early warning,damage location,and damage extent identification.The multi-class pattern classification algorithm of C-support vector machine and the regression algorithm of ε-support vector machine are engaged to identify the damage location and damage extent,respectively.For verifying the proposed method,both of the proposed method and the optimization method are used to deal with the measured data obtained from a specific railway continuous girder model bridge.The results show that the proposed method can not only identify the damage location correctly,but also obtain the damage extent which is consistent with the experimental results accurately.By uncoupling finite element analysis and damage identification,normalizing the index,and seeking the separation hyper plane with maximum margin,the proposed method has more favorable advantages in generalization and anti-noise.As a result,it has the ability to identify the damage location and extent,and can be applied to the damage identification in real bridge structures.