Two failing wooden bridges in southeast Benton County will be closed to some vehicles until funding can be found to replace them with concrete structures.

The Benton County Board of Commissioners voted unanimously on Tuesday to place weight restrictions on the Irish Bend Road and Dodge Island Road bridges, both located east of Highway 99W in a rural area outside Monroe.

The estimated replacement cost for both spans is about $3.6 million, according to Laurel Byer, the engineering and survey program manager for the Benton County Public Works Department.

“We’ve applied to the state for grant funding to fix those bridges because we knew they were in a poor state,” Byer told the commissioners.

The Irish Bend Road Bridge will be restricted to 14 tons, which means heavy vehicles such as large farm machinery, fire engines and garbage trucks will no longer be able to use the bridge. The bridge on Dodge Island Road will have an 8-ton limit, which also bars school buses and ambulances.

Passenger vehicles still will be able to use both bridges.

While the bridges are not heavily used, Byer said, the restrictions will create some hardships for the families who depend on them for road access.

“There are impacts, unfortunately, for those property owners,” she said.

She told the commissioners her department is working to map out alternate routes that will allow heavy vehicles to bypass the compromised bridges.

The weight restrictions follow a Feb. 6 inspection by an engineer with the Oregon Department of Transportation, who found both spans need strengthening to meet new state load rating standards. Ironically, the lower limits should strengthen the county’s case for grant funding from ODOT.

“It’s kind of a double-edged sword, unfortunately,” Byer said. “We have to put limits on these bridges in order to apply for grants.”

Weight restrictions for the two bridges are to go into effect no later than May 15. The grants, if approved, would be available in about two years.

In other action, the board:

• Approved a petition to annex the Belknap property into the Philomath Rural Fire Protection District after a brief public hearing. The fire district’s board previously accepted the petition.

• Adopted a policy defining reasonable accommodations for people with disabilities for the county’s Special Transportation Program.

• Approved some minor changes to the operational agreement between the board and the Community Health Centers of Benton and Linn Counties.

• Accepted right of way along Northwest Harrison Boulevard from Beit Am Jewish Community for road and utility purposes.

Reporter Bennett Hall can be reached at 541-758-9529 or Follow him on Twitter at @bennetthallgt.