DETECTION OF THROUGH-DECK CRACKS INITIATED BETWEEN LONGITUDINAL AND TRANSVERSE RIBS.

Abstract

 Fatigue cracks that are visually difficult to inspect will initiate and propagate in the orthotropic steel deck. The authors have proposed a method to detect fatigue cracks by monitoring strain changes out of loading because the balance of residual stress introduced by welding changes when fatigue crack initiates and propagates. In this study, by measuring the strain at the lower surface of the deck plate or the outer surface of the U-shaped ribs during the unloading condition, it was found that it is possible to detect the initiation and progression of fatigue cracks at the weld root between the orthotropic steel deck plate and the U-shaped ribs, which is one of the visually difficult-to-inspect locations of steel bridges. In addition, monitoring using IoT data loggers was conducted, showing that low-cost fatigue damage monitoring is possible.