US Bridges

337 Boulder/Basin over East Fork Yaak River

Fair

Lincoln County, Montana · JCT With Yaak 92 · Structure no. 011404000000185

Built
1981
44 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
60 ft
1 main span
Daily traffic
60
1994 count
Owner
Federal
U.S. Forest Service

About this bridge

337 Boulder/Basin over East Fork Yaak River is a prestressed concrete stringer/multi-beam or girder carrying 337 Boulder/Basin over East Fork Yaak River in Lincoln County, Montana. It was built in 1981, so it is 44 years old, younger than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 60 vehicles a day, projected to reach 90 by 2045. The structure is 60 ft (18.3 m) long and 17 ft wide. If it were closed, the detour would be 29.8 mi (48 km).

Location

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Carries337 Boulder/Basin
CrossesEast Fork Yaak River
LocationJCT With Yaak 92
RouteFederal Lands Road 337
CountyLincoln County
StateMontana
Coordinates48.94367, -115.4914
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating43.5 US tons
Inventory rating33.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadHS 20
Structure length60 ft (18.3 m)
Longest span59 ft (18 m)
Deck width17 ft (5.1 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic60 (1994)
Projected traffic90 by 2045
Trucks—
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed29.8 mi (48 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerU.S. Forest Service
Maintained byU.S. Forest Service
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 337 Boulder/Basin over East Fork Yaak River built?

It was built in 1981, making it 44 years old in 2025.

What condition is 337 Boulder/Basin over East Fork Yaak River in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in August 2024.

How much traffic does 337 Boulder/Basin over East Fork Yaak River carry?

About 60 vehicles per day (1994 count).

How long is 337 Boulder/Basin over East Fork Yaak River?

The structure is 60 ft (18.3 m) long with a longest span of 59 ft (18 m) and a deck 17 ft wide.

Who owns 337 Boulder/Basin over East Fork Yaak River?

It is owned by the U.S. Forest Service.