US Bridges

IRR - S 313 over Williams Coulee

Good

Big Horn County, Montana · 1M S Hardin · Structure no. 000000202106632

Built
2021
4 years old
Condition
Good
inspected December 2023
Type
Slab
Concrete
Length
73 ft
3 main spans
Daily traffic
899
2023 count
Owner
State
State Highway Agency

About this bridge

IRR - S 313 over Williams Coulee is a concrete slab carrying IRR - S 313 over Williams Coulee in Big Horn County, Montana. It was built in 2021, so it is 4 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 899 vehicles a day, roughly 17% of them trucks, projected to reach 944 by 2043. The structure is 73 ft (22.3 m) long and 35 ft wide. If it were closed, the detour would be 80.2 mi (129 km).

Location

Open in Google Maps
CarriesIRR - S 313
CrossesWilliams Coulee
Location1M S Hardin
RouteState Highway 313
CountyBig Horn County
StateMontana
Coordinates45.70388, -107.62193
Functional classRural Major Collector

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 inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating50 US tons
Inventory rating39 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length73 ft (22.3 m)
Longest span28 ft (8.5 m)
Deck width35 ft (10.8 m)
Roadway width33 ft (10.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic899 (2023)
Projected traffic944 by 2043
Trucks17%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed80.2 mi (129 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 313 over Williams Coulee built?

It was built in 2021, making it 4 years old in 2025.

What condition is IRR - S 313 over Williams Coulee 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 December 2023.

How much traffic does IRR - S 313 over Williams Coulee carry?

About 899 vehicles per day (2023 count), of which roughly 17% are trucks.

How long is IRR - S 313 over Williams Coulee?

The structure is 73 ft (22.3 m) long with a longest span of 28 ft (8.5 m) and a deck 35 ft wide.

Who owns IRR - S 313 over Williams Coulee?

It is owned by the State Highway Agency.