Sudden ground motions such as earthquakes sometimes cause serious damage in railway structures. For evaluating the structural integrity after the shock, damage condition of superstructures (or the upper part of substructures) is primarily investigated with the unaided eye. The results are basically subjective, and the structural integrity is evaluated only from the region that could be observed. Accordingly, in order to quantify the structural integrity objectively, an AE testing is tried to apply for the railway structures. In damaged concrete materials, it is known that secondary AE activity from existing defects are readily generated, and based on the Kaiser effect, damage degree could be quantified. In the monitoring of railway structures, however, except for AE signals from the defect, directly induced AE signals by the acceleration of the train passage could be detected. In the present paper, frequency characteristics of such AE signals as secondary AE signals and noise signals are elucidated through laboratory and in-situ experiments. The damage is quantified in an actual concrete pier based on the AE activity of raw AE data including noise signals, and extracted AE data generated from existing cracks, respectively. The results suggest that the quantitative evaluation of damage degree might be possible with the extracted AE activity, however, more data should be collected to classify damage degree reasonably.

No abstract

No abstract

No abstract

No abstract