US Bridges

RD 472 over Yaak River

Fair

Lincoln County, Montana · Yaak River · Structure no. 011404000000206

Built
1954
71 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
149 ft
3 main spans
Daily traffic
50
1993 count
Owner
Federal
U.S. Forest Service

About this bridge

RD 472 over Yaak River is a steel stringer/multi-beam or girder carrying RD 472 over Yaak River in Lincoln County, Montana. It was built in 1954, so it is 71 years old, older 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 5 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 50 vehicles a day, projected to reach 75 by 2045. The structure is 149 ft (45.4 m) long and 16 ft wide. If it were closed, the detour would be 24.9 mi (40 km).

Location

Open in Google Maps
CarriesRD 472
CrossesYaak River
LocationYaak River
RouteFederal Lands Road 472
CountyLincoln County
StateMontana
Coordinates48.72974, -115.87453
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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 12 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating39.7 US tons
Inventory rating30.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans3
Design loadHS 25 or greater
Structure length149 ft (45.4 m)
Longest span55 ft (16.8 m)
Deck width16 ft (5 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (1993)
Projected traffic75 by 2045
Trucks—
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed24.9 mi (40 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost$40,000
NavigationNo navigation control on waterway

Frequently asked questions

When was RD 472 over Yaak River built?

It was built in 1954, making it 71 years old in 2025.

What condition is RD 472 over 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 RD 472 over Yaak River carry?

About 50 vehicles per day (1993 count).

How long is RD 472 over Yaak River?

The structure is 149 ft (45.4 m) long with a longest span of 55 ft (16.8 m) and a deck 16 ft wide.

Who owns RD 472 over Yaak River?

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