Abstract
In this study, the authors identified the vibration characteristics (natural frequency and vibration modes) of a 24-span steel railway bridge that has been used for 86 years, through a passing train test and an impulse hummer test. The 24 spans have the same structure and are used under the same loading condition and almost the same environmental condition. Identified vibration characteristics (up to 70Hz for 12 modes) were compared, and it was found that there are no significant differences in vibration characteristics among the 24 slabs and even after 86 years of operation, vibration characteristics can be kept homogeneous through appropriate maintenance. In addition, the relation between the identified vibration characteristics and the bridge/train specifications was analyzed, and it was clarified that at the measurement points nearer to rail joints, mode amplitude becomes larger and its influence varies with modes.
