The Minnesota Department of Transportation (MnDOT) (Saint Paul, Minnesota, USA) successfully used phased array ultrasonic testing (PAUT) with three-dimensional (3-D) scanning technology to identify and map corrosion and section loss on four steel bridge structures.
According to MnDOT, the system detected and measured corrosion more accurately than traditional methods, such as conventional single-beam ultrasonic devices and field measuring techniques.
One of the advantages, it says, is that the system provides thousands more data points, which allow engineers to more accurately measure steel thickness and predict maintenance issues. Another benefit is a quicker collection of corrosion mapping data, which reduces the amount of time that inspectors spend on bridges.
With up to 256 sound-wave emitters, the PAUT devices can focus at multiple locations and provide better defect detection than single-beam devices. With transducers and software, they can also be used for crack detection and weld inspection.
Minnesota has ~13,000 bridges, and MnDOT says it plans to begin deploying the system to conduct corrosion inspections on other steel bridges and ancillary structures.
It also plans to revise the nondestructive testing content in its inspection manual, targeting bridge inspection units, bridge engineers, and bridge owners.
Source: MnDOT, dot.state.mn.us.