US Bridges

IRR - S 39 over Rr-Power Plant Road

Fair

Rosebud County, Montana · South Edge Colstrip · Structure no. P00039022+01521

Built
1981
44 years old
Condition
Fair
inspected July 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
261 ft
4 main spans
Daily traffic
1,250
2023 count
Owner
State
State Highway Agency

About this bridge

IRR - S 39 over Rr-Power Plant Road is a prestressed concrete stringer/multi-beam or girder carrying IRR - S 39 over Rr-Power Plant Road in Rosebud 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 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 1,250 vehicles a day, roughly 3% of them trucks, projected to reach 1,313 by 2043. The structure is 261 ft (79.5 m) long and 42 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesIRR - S 39
CrossesRr-Power Plant Road
LocationSouth Edge Colstrip
RouteState Highway 39
CountyRosebud County
StateMontana
Coordinates45.87475, -106.62661
Functional classRural Minor Arterial

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.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJuly 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 geometry6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating40 US tons
Inventory rating31 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length261 ft (79.5 m)
Longest span67 ft (20.3 m)
Deck width42 ft (12.9 m)
Roadway width39 ft (12 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,250 (2023)
Projected traffic1,313 by 2043
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesRailroad
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$960,000
NavigationNot applicable (no waterway)

Frequently asked questions

When was IRR - S 39 over Rr-Power Plant Road built?

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

What condition is IRR - S 39 over Rr-Power Plant Road 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 July 2024.

How much traffic does IRR - S 39 over Rr-Power Plant Road carry?

About 1,250 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is IRR - S 39 over Rr-Power Plant Road?

The structure is 261 ft (79.5 m) long with a longest span of 67 ft (20.3 m) and a deck 42 ft wide.

Who owns IRR - S 39 over Rr-Power Plant Road?

It is owned by the State Highway Agency.