In this study, the authors examined whether fatigue crack propagation inside box girders of steel railway bridges can be detected by measuring static strain without loading. Monitoring focused on cracks at the weld toe of the scallop in the cross ribs and at the welding between longitudinal and cross ribs. Monitoring results revealed that crack propagation can be evaluated by observing static strain changes. In addition, fatigue tests were conducted to investigate the tendency of static strain change by crack propagation at the welding between longitudinal and cross ribs. The results confirmed the reliability of crack evaluation through static strain monitoring.
