2018 Volume 74 Issue 3 Pages 158-175
More than 50 years have elapsed since the fist introduction of PC sleepers, and some damage sleepers have also been confirmed. Although it is necessary to detect and replace damaged PC sleepers properly, it is difficult to find the damages in the ballasted track because inspectors can only see the upper surface of the sleepers. In this study, various vibration and sound measurements were conducted to develop a damaged PC sleeper detection method using modal characteristics. The bending tests, vibration and sound measurements, and numerical analyses revealed that the natural frequencies are clearly dropped due to open cracks at the cross section of rail seat, and the vibration measurement of the actual damaged PC sleepers clarified that the natural frequency of third mode have high correlation with the damage degree. In addition, a simple detection method using a sound level meter was proposed and applied to the test line and actual rail lines. As a result, it is possible to detect damaged PC sleepers efficiently with the similar accuracy of multi-point detailed measurement method.