Vibration-based damage identification in railway concrete sleepers

In this study, concrete sleepers, widely used in railway industry, are a subject to damage identification as mechanical failure of these components can lead to tragic consequences. Three-point bending tests are conducted on four concrete sleepers. Two sleepers are loaded until failure and are subjected to experimental modal analysis, while a multi-stage damage severity scheme is applied to other two sleepers. This scheme implies that sleepers are loaded until the appearance of the first crack. A subsequent experimental modal analysis is performed. Then these sleepers are loaded until load equal to 1.5 times of the load corresponding to the first crack. Experimental modal analysis procedure is repeated and dynamic structural parameters, namely, natural frequencies, damping and mode shapes are extracted and compared among sleepers at healthy and damaged conditions.