Abstract
Fatigue cracks have been recently reported at weld root of deckplate-U type rib connection in orthotropic steel deck bridges on heavy traffic route. These cracks propagate to the upper surface of deckplate, that makes it difficult to detect them during visual inspection. With the purpose of developing a reliable and practical non-destructive inspection method for the cracks, this paper discusses an ultrasonic testing method using SV waves by critical angle beam probe. A reliable technique for the sensitivity calibration was proposed. Based on ultrasonic testing for fatigue crack specimens and a damaged deckplate on actual bridge, applicability of the proposed ultrasonic inspection method was confirmed.
