A truck carrying an oversized load hit the Marys River Bridge in south Corvallis around 10:30 a.m. Friday, buckling two lateral support beams and damaging most of the overhead crossbraces.

The bridge on Oregon Highway 99W just south of downtown is made up of two separate steel structures carrying northbound and southbound traffic. The damage occurred on the northbound structure.

The Oregon Department of Transportation closed the bridge to northbound traffic for about an hour Friday in order for bridge inspectors to determine the extent of the damage. Although ODOT reopened the bridge to cars and small trucks, the department is rerouting oversized trucks traveling north on Highway 99 to the Corvallis bypass, a one-mile detour around the damaged bridge, until further notice. Traffic flow could be interrupted on and off for up to four weeks until the bridge is repaired.

It was not known who owned the truck or what it was carrying that did the damage. The incident was not reported to police.

Jeff Swanstrom, a bridge inspector with ODOT, estimates it will probably take a couple of weeks to fix the bridge. He said he thinks the truck that did the damage must have had some sort of protruding equipment or load because it hit both sides of each of the six upper beams. The bridge has a 14 foot, 9 inch clearance. The bottom support system looks stable, he said.

The engineer who will design the repair work will inspect the bridge Monday. The whole front portal may need to be replaced.

"The bridge is historical, so any replacement members will have to match," Swanstrom said.

The Marys River Bridge was built in 1932 by the Oregon State Highway Commission.

Bob Doran, district manager for ODOT, said there are no plans to replace the bridge with a more modern version.

"It will be here for our lifetime," he said. "Even if it is replaced, the bridge will stay in this location because of its unique design and historical nature."