Fracture precursors in a working girder crane: AE natural-time and b-value time series analyses

The operational capability of an in-service double girder bridge crane is assessed by Acoustic Emission (AE) monitoring technique. A network of AE sensors are applied to one beam of the crane bridge. From this perspective, AE time series are analyzed to reveal possible collapse precursors in different positions of the monitored beam. The results of the analysis demonstrate an asymmetric damage pattern with the criticality condition identified in a portion of the monitored structural element. This evidence can be interpreted as signature of initiation or propagation of fatigue cracks.