Abstract
In order to detect the damages of PC sleeper in the ballast track which cannot be inspected visually, the damage detection system using vibration mode characteristic of PC sleepers was developed in this paper. As a result of the vibration measurement test that conducted in parallel to the bending test, it was confirmed that the natural frequencies begin to fall when the load of 1.2 times or more of crack load acted. And, it was confirmed that the natural frequenciy of 3rd mode in which the influence of damage appears greatly and influence of ballast or rails don't appear is suitable for detection of the opening crack of the bottom of rail place from the vibration measurement test results of PC sleepers which have real damage and the vibration measurement test results in the examination railway line. Furthermore, towards practical use, the damage detection by single point measurement and simple signal processing was considered, and it was shown that the same detection accuracy as multipoint measurement is securable.
