The Minnesota Department of Transportation is evaluating whether unmanned aerial systems can take some of the cost and danger out of bridge inspections.
As the nation’s infrastructure ages, bridge inspections are critical -- but expensive. Having people check the undersides of bridges from scaffolding or special trucks with telescoping arms takes time, costs money and endangers workers. That’s why the Minnesota Department of Transportation has been evaluating the use of drones to inspect some of the state’s bridges.
Besides keeping costs down, improving safety and avoiding the traffic disruptions that manual bridge inspections can cause, the use of unmanned aerial systems could also improve the quality of inspections. Therefore, state officials wanted to test a range of imaging technologies associated with drones, such as high-definition still images, videos, infrared sensors and 3-D imaging software.
They did so in two phases. First, the project team used drones to inspect four bridges and evaluated their effectiveness in improving inspection quality and inspector safety. Then they tested UAS imaging capabilities on the state’s John A. Blatnik Bridge in Duluth. Specifically, the team wanted to know how drones performed in confined spaces and how they aided in inspection planning and emergency responses to bridge hits when it’s unsafe for inspectors to investigate.
The project team inspected three types of bridges -- a steel box girder, a steel culvert and an arch bridge -- using SenseFly’s albris drone, which is designed for mapping and inspection work.
Based on those tests, department officials plan to identify the types, locations and conditions of bridges best suited to drone inspections. They will also issue a report detailing new technology that is specific to inspections, a cost comparison to traditional methods, the advantages and disadvantages of using drones for bridge inspections and a best-practices document.
Eventually, department officials want to award a statewide contract for all bridges that meet the criteria for drone inspections.
Editor's note: This article was changed Oct. 10 to update the name of the SenseFly drone.
NEXT STORY: What drones mean for surveillance