US Bridges

Midby RD over Big Muddy Creek 024

Good

Sheridan County, Montana · 7M W Plentywood · Structure no. L46429000+06001

Built
1987
38 years old
Condition
Good
inspected January 2024
Type
Slab
Concrete Continuous
Length
79 ft
3 main spans
Daily traffic
22
2023 count
Owner
County
County Highway Agency

About this bridge

Midby RD over Big Muddy Creek 024 is a concrete continuous slab carrying Midby RD over Big Muddy Creek 024 in Sheridan County, Montana. It was built in 1987, so it is 38 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 22 vehicles a day, roughly 3% of them trucks, projected to reach 23 by 2043. The structure is 79 ft (24.1 m) long and 27 ft wide. If it were closed, the detour would be 18 mi (29 km).

CarriesMidby RD
CrossesBig Muddy Creek 024
Location7M W Plentywood
RouteCounty Highway 46429
StateMontana
Coordinates48.76634, -104.68428
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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating47.2 US tons
Inventory rating36.4 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length79 ft (24.1 m)
Longest span30 ft (9.1 m)
Deck width27 ft (8.3 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic22 (2023)
Projected traffic23 by 2043
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed18 mi (29 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 Midby RD over Big Muddy Creek 024 built?

It was built in 1987, making it 38 years old in 2025.

What condition is Midby RD over Big Muddy Creek 024 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 January 2024.

How much traffic does Midby RD over Big Muddy Creek 024 carry?

About 22 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is Midby RD over Big Muddy Creek 024?

The structure is 79 ft (24.1 m) long with a longest span of 30 ft (9.1 m) and a deck 27 ft wide.

Who owns Midby RD over Big Muddy Creek 024?

It is owned by the County Highway Agency.