US Bridges

331 Rabbit/Obrien over Obrien CR

Good

Lincoln County, Montana · Just Before JCT With 752 · Structure no. 011404000000047

Built
1979
46 years old
Condition
Good
inspected August 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
29 ft
1 main span
Daily traffic
20
1994 count
Owner
Federal
U.S. Forest Service

About this bridge

331 Rabbit/Obrien over Obrien CR is a prestressed concrete stringer/multi-beam or girder carrying 331 Rabbit/Obrien over Obrien CR in Lincoln County, Montana. It was built in 1979, so it is 46 years old, younger than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 20 vehicles a day, projected to reach 30 by 2045. The structure is 29 ft (8.7 m) long and 24 ft wide. If it were closed, the detour would be 29.8 mi (48 km).

Location

Open in Google Maps
Carries331 Rabbit/Obrien
CrossesObrien CR
LocationJust Before JCT With 752
RouteFederal Lands Road 331
CountyLincoln County
StateMontana
Coordinates48.55859, -115.79449
Functional classRural Local

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating31.1 US tons
Inventory rating24.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadHS 20
Structure length29 ft (8.7 m)
Longest span27 ft (8.2 m)
Deck width24 ft (7.3 m)
Roadway width23 ft (7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20 (1994)
Projected traffic30 by 2045
Trucks—
Lanes on structure2
Traffic directionTwo-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 331 Rabbit/Obrien over Obrien CR built?

It was built in 1979, making it 46 years old in 2025.

What condition is 331 Rabbit/Obrien over Obrien CR in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in August 2024.

How much traffic does 331 Rabbit/Obrien over Obrien CR carry?

About 20 vehicles per day (1994 count).

How long is 331 Rabbit/Obrien over Obrien CR?

The structure is 29 ft (8.7 m) long with a longest span of 27 ft (8.2 m) and a deck 24 ft wide.

Who owns 331 Rabbit/Obrien over Obrien CR?

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