US Bridges

US 12 over RR

Fair

Powell County, Montana · Garrison · Structure no. P00088000+06091

Built
1949
76 years old
Condition
Fair
inspected October 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
204 ft
3 main spans
Daily traffic
1,416
2023 count
Owner
State
State Highway Agency

About this bridge

US 12 over RR is a steel continuous stringer/multi-beam or girder carrying US 12 over RR in Powell County, Montana. It was built in 1949, so it is 76 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 1,416 vehicles a day, roughly 7% of them trucks, projected to reach 1,487 by 2043. The structure is 204 ft (62.1 m) long and 35 ft wide. If it were closed, the detour would be 19.9 mi (32 km).

Location

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CarriesUS 12
CrossesRR
LocationGarrison
RouteState Highway 88
CountyPowell County
StateMontana
Coordinates46.52442, -112.79839
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment7: Better than present minimum criteria
Operating rating44 US tons
Inventory rating34 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length204 ft (62.1 m)
Longest span72 ft (21.9 m)
Deck width35 ft (10.7 m)
Roadway width32 ft (9.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,416 (2023)
Projected traffic1,487 by 2043
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesRailroad
Detour if closed19.9 mi (32 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was US 12 over RR built?

It was built in 1949, making it 76 years old in 2025.

What condition is US 12 over RR 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 October 2024.

How much traffic does US 12 over RR carry?

About 1,416 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is US 12 over RR?

The structure is 204 ft (62.1 m) long with a longest span of 72 ft (21.9 m) and a deck 35 ft wide.

Who owns US 12 over RR?

It is owned by the State Highway Agency.