Damage assessment of a railway bridge based on vibration monitoring

To confirm changes in the dynamic behavior of the damaged and the retrofitted bridge, multiple times of vibration monitoring were conducted on an actual railway bridge with crack damage before and after retrofitting. First, to clarify the vibration properties of railway bridges with a cracked crossbeam, we conducted finite element analysis of railway bridge model for an original retrofitted bridge and a model of a damaged bridge. Then to identify the modal properties of both states, multiple times of vibration measurement were conducted for the actual bridge. We clarified that dominant frequencies were almost identical in both states, but the occurrence of dominant frequencies differed slightly, which may have been caused by the difference in effective mass between the two states. This may indicate that the difference between the two states can be identified statistically with sufficient data to enable evaluation.