EVALUATION OF FLOATING SLEEPERS ON BRIDGES USING FULL-FIELD IMAGE MEASUREMENT

Abstract

 Sleeper floating is a typical abnormality on railways, but it is difficult to detect visually and various assessment methods are being developed. On the other hand, although there have been reports of cases leading to damage of track components, evaluation methods for sleeper floating on bridges have not been investigated to the same extent as in roadbed sections. In this study, a full-field image measurement method based on digital image correlation was applied to video images taken from oblique angles below a bridge, and a homography transformation was used to develop a method for extracting all the floating sleepers on a single bridge in a single shot. As a result of applying the method to 18 sleepers on a bridge on a real railway line, it was found that seven sleepers were in a floating state based on the difference in displacement waveforms between the sleepers and the bridge directly below them, and that the estimated results were consistent with the results of the gap survey in the field.