Phased array ultrasonic inspection of rib-to-deck welded joints in orthotropic steel decks

Over the last decade, fatigue cracking has been observed in welded joints between the trapezoidal rib and the deck plate in many orthotropic steel deck bridges in Japan. Considering fatigue cracking at rib-to-deck welded joints can cause pavement damage and thus compromise transportation safety, it is necessary to detect and repair fatigue cracks at rib-to-deck welded joints at the early stage of development. This paper presents a new inspection method for rib-to- deck welded joints in orthotropic steel decks using phased array ultrasonic testing. Although existing inspection methods for rib-to-deck welded joints aim at detecting fatigue cracks in the deck plate solely, the developed method examines both the deck plate and the weld bead simultaneously by using an electrically driven scanner holding twin phased array ultrasonic probes. The developed inspection method is implemented at the Meiko-Chuo Bridge, a steel cable-stayed bridge, and the crack detection ability is examined.