INSPECTING BRIDGE SUBSTRUCTURE USING ADVANCED ULTRASONIC METHODS

There are several hundreds of thousands of steel bridges that have submerged substructures also known as piles, around the world. Due to underwater corrosion, the piles suffer wall losses which if undetected and unmitigated, could lead to catastrophic failure of the bridge structure. The currently used inspection processes are time consuming, expensive, hazardous and are highly dependent on the operator's skills. An innovative long range ultrasonic technique that inspects piles for wall loss from above the water line is discussed in this paper. Two different methods of generating long range ultrasound in H-piles and sheet piles are discussed. The reflected ultrasonic energy is used to detect and characterize the wall loss defects using an interpretation procedure developed on the basis of field tests on piles. The reported method is relatively inexpensive as it cuts down on the need for sending underwater divers, inspecting at high scan rates.