US Bridges

IRR - S 350 over Big Muddy Creek

Fair

Sheridan County, Montana · 9M NW Froid · Structure no. S00350003+00001

Built
1957
68 years old
Condition
Fair
inspected February 2024
Type
Tee Beam
Concrete Continuous
Length
110 ft
3 main spans
Daily traffic
28
2023 count
Owner
State
State Highway Agency

About this bridge

IRR - S 350 over Big Muddy Creek is a concrete continuous tee beam carrying IRR - S 350 over Big Muddy Creek in Sheridan County, Montana. It was built in 1957, so it is 68 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 28 vehicles a day, roughly 21% of them trucks, projected to reach 29 by 2043. The structure is 110 ft (33.5 m) long and 27 ft wide. If it were closed, the detour would be 29.2 mi (47 km).

Location

Open in Google Maps
CarriesIRR - S 350
CrossesBig Muddy Creek
Location9M NW Froid
RouteState Highway 350
CountySheridan County
StateMontana
Coordinates48.41844, -104.563
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionFebruary 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 geometry6: Equal to present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating50 US tons
Inventory rating30 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 15
Structure length110 ft (33.5 m)
Longest span70 ft (21.3 m)
Deck width27 ft (8.1 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic28 (2023)
Projected traffic29 by 2043
Trucks21%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed29.2 mi (47 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 350 over Big Muddy Creek built?

It was built in 1957, making it 68 years old in 2025.

What condition is IRR - S 350 over Big Muddy Creek 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 February 2024.

How much traffic does IRR - S 350 over Big Muddy Creek carry?

About 28 vehicles per day (2023 count), of which roughly 21% are trucks.

How long is IRR - S 350 over Big Muddy Creek?

The structure is 110 ft (33.5 m) long with a longest span of 70 ft (21.3 m) and a deck 27 ft wide.

Who owns IRR - S 350 over Big Muddy Creek?

It is owned by the State Highway Agency.