Utah Department of Transportation (UDOT) crews recently inspected one of Salt Lake's "Spaghetti Bowl" bridges with ultrasonic testing.
This technology uses a transducer to transmit high-frequency sound waves into difficult-to-see parts of a bridge, searching for damage, deterioration or any other factors that may raise safety concerns. The bridge, built in 1985, connects northbound Interstate 215 to westbound Interstate 80.
"Ultrasonic testing is one of the many tools we use when assessing the condition of bridges," UDOT Bridge Management engineer Becky Nix said.
Although not part of the standard inspection process, Nix said ultrasonic testing is used in specialty situations to evaluate critical bridge elements.
"We want everyone to know that when they are driving on one of our bridges, they are going to be safe," Nix said.
The typical bridge inspection process involves detailed data collection, including written and photo documentation, and ranking scales. Nix said that, occasionally, inspection crews use ultrasonic testing, LiDAR (eye-safe laser beams), ground penetrating radar or infrared thermography to gather data on a bridge's condition.
All inspection standards are set and evaluated by the American Association of State Highway and Transportation Officials (AASHTO) and the Federal Highway Administration (FHWA). UDOT bridge inspection crews use these standards to perform biennial inspections of more than 3,000 state and locally owned bridges.
"We complete 150-160 bridge inspections per month," Nix said. "It's a busy schedule but this data is so valuable. They help to ensure public safety and help prioritize future projects. We're constantly collecting data so that we can make smarter, safer decisions for the state's infrastructure."
For example, data from the January inspection of the Veyo Arch bridge on State Route 18 identified critical defects that needed to be addressed right away. The repairs began within a month.
