Martin Kidston

(Missoula Current) Another bridge in Missoula County has been partially closed to traffic until crews can replace a pile supporting a portion of the structure.

The county on Tuesday approved a $19,000 contract with HDR Engineering to design a pile replacement for the bridge, which spans Glacier Creek in Condon.

“The Montana Department of Transportation is willing to pay for that replacement,” said Shane Stack, the county's director of Public Works. “We have an agreement with MDT for $38,000 for the design and replacement of the pier. So far they're fully on board with what we're proposing.”

Current estimates for repair costs stand at more than $100,000, according to the county. Once a better estimate is developed, MDT would likely cover the expense using funds provided by the Legislature in Senate Bill 536.

“There are multiple piles on this bridge, but an upstream pile was damaged. “We had to close off about one-third of the bridge. Where it was maybe a two-lane bridge before, it's now maybe a lane-and-a-half.”

The county believes ice flows damaged an upstream pile on the bridge. (Missoula County photo)
The county believes ice flows damaged an upstream pile on the Glacier Creek bridge. (Missoula County photo)

The bridge is the third in Missoula County needing repairs. In November, the county permanently closed Boy Scout Bridge in Seeley Lake over structural concerns.

Stack said the wooden piles on that bridge, built in 1937, are rotting out.

“I think the piles are failing on Boy Scout Bridge,” Stack said. “This one on Glacier Creek, I think ice floes damaged the upstream pile. The proposed fix is to just drive a steel pile in front of the damaged wooden pile.”

Also in November, state engineers placed the bridge on Rock Creek Road in “scour critical” condition, largely due to channel erosion. The county must create a plan of action, including a detour route to Interstate 90, in the event the bridge were to fail or close for repairs.

The county also must pursue a mitigation plan for the Rock Creek structure in order to remain illegible for federal or state assistance to address repairs. Last month, the county approved a $32,000 contract with the WGM Group to design a scour mitigation plan.