US Bridges

IRR - S 251 over Drainage

Fair

Roosevelt County, Montana · 20M NE Poplar · Structure no. S00251015+05001

Built
1948
77 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
26 ft
1 main span
Daily traffic
145
2023 count
Owner
State
State Highway Agency

About this bridge

IRR - S 251 over Drainage is a wood or timber stringer/multi-beam or girder carrying IRR - S 251 over Drainage in Roosevelt County, Montana. It was built in 1948, so it is 77 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 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 145 vehicles a day, roughly 11% of them trucks, projected to reach 152 by 2043. The structure is 26 ft (7.9 m) long and 27 ft wide. If it were closed, the detour would be 14.9 mi (24 km).

Location

Open in Google Maps
CarriesIRR - S 251
CrossesDrainage
Location20M NE Poplar
RouteState Highway 251
CountyRoosevelt County
StateMontana
Coordinates48.32865, -105.08333
Functional classRural Major Collector

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.
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating45 US tons
Inventory rating30 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadH 15
Structure length26 ft (7.9 m)
Longest span25 ft (7.6 m)
Deck width27 ft (8.3 m)
Roadway width26 ft (7.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic145 (2023)
Projected traffic152 by 2043
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.9 mi (24 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was IRR - S 251 over Drainage built?

It was built in 1948, making it 77 years old in 2025.

What condition is IRR - S 251 over Drainage 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 IRR - S 251 over Drainage carry?

About 145 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is IRR - S 251 over Drainage?

The structure is 26 ft (7.9 m) long with a longest span of 25 ft (7.6 m) and a deck 27 ft wide.

Who owns IRR - S 251 over Drainage?

It is owned by the State Highway Agency.