Bridge strike on I-15 overpass near Blackfoot
features quick response, decisive action

Riverton Road's overpass, about a mile south of Blackfoot, was struck by a track hoe riding on the trailer of a semi-truck during the morning of Aug. 20. Riverton Road crosses Interstate 15 at that location. The overpass remains closed pending repairs later this fall/winter. Pictured above, the track hoe sits at a 45-degree angle to the side of the semi trailer following the bridge strike.

Three concrete structural-support beams sustained extensive damage, prompting closure for the safety of the motoring public. Pictured below is the worst of the damage sustained during the bridge strike.

Northbound travel lanes of I-15 were temporarily closed at the location. They reopened by mid-afternoon.

The incident featured quick response and resourceful solutions.

The bridge strike occurred around 7:50 a.m. A call was dispatched from Idaho State Communications to ITD minutes later, and by 8:15 a.m., District 5 Maintenance Operations Manager Steve Gertonson was on site, along with the crew from the Blackfoot maintenance shed.

Within just a few hours, Gertonson said ITD had finalized repair plans with the company that struck the overpass and their insurance provider.

"An engineering firm was retained by the track hoe owners to begin making repair drawings, and meanwhile the District 5 Bridge and Building crew cleaned hanging debris from the underside of the bridge and a containment system (pictured at bottom) was used to capture any other falling debris and ensure that nothing impacted cars beneath the overpass traveling on the interstate," he added. Gertonson said the containment system consisted of canvas tacked to the structure.

"We sent a maintenance guy up in a scissor lift to take pictures of the damage, then sent those pictures to State Bridge Engineer Matt Farrar in Boise for his review," explained District Engineer Ed Bala.

The track hoe is owned by Cannon Builders Inc., of Blackfoot, a company specializing in bridge construction and repair. Once ITD approves the plans, Cannon will perform the repairs using its own forces.

ITD does not yet know the cost of repairs, but crews will need to replace multiple structural beams and bridge-deck surfaces.

Published 08-28-15