3/18/2010
Construction under way on two bridges in Lost River Valley
RIGBY - Construction is under way on two bridges in Lost River Valley, the Idaho Transportation Department (ITD) announced.
Crews are replacing the Knighton Lane and East Darlington bridges that cross the Big Lost River in Butte and Custer counties, respectively.
Roads to the bridges are closed to through traffic, with traffic detoured to neighboring county lanes. The roads will be closed until the bridges are finished this summer.
ITD plans to complete the bridges, including their approaches, by mid-August, with the East Darlington Bridge to be finished as early as June.
Located two miles northeast of Moore and one mile east of Darlington, the old bridges were nearly a century old. Records at ITD Headquarters in Boise show the East Darlington Bridge was constructed in 1915 and the Knighton Lane Bridge was constructed in 1920.
Crews removed the East Darlington Bridge last week and the Knighton Lane Bridge in January. Steel trusses with timber decks, these old bridges were showing their age.
Last year, ITD rated the sufficiency of these one-lane spans at 24.3 and 34.4 out of 100. A sufficiency rating below 50 indicates the bridge is due for replacement.
The new bridges will be concrete. The Knighton Lane Bridge will be 126 feet long, and the East Darlington Bridge will be 93 feet long.
Crews now are driving steel piles 50 to 70 feet into the ground as footings for new bridge abutments, which will be poured later this spring.
ITD awarded Cannon Builders of Blackfoot the $1.3 million contract for the Knighton Lane Bridge and the $605,000 contract for the East Darlington Bridge.
Butte County is sponsor of the Knighton Lane Bridge, while the Lost River Highway District is sponsor of the East Darlington Bridge. Each entity will pay 7.34 percent of the cost of its bridge replacement, with the federal government picking up the balance of the expense. ITD is administering the bridge project.
For information on construction projects and road conditions of Idaho highways, visit the Idaho Traveler Services Web site at 511.idaho.gov or dial 5-1-1 on phones within the state. Outside Idaho, dial toll‑free (888) 432‑7623. Information is updated as conditions change.