US Bridges

IRR - S 313 over Soap Creek

Good

Big Horn County, Montana · 9M SW ST Xavier · Structure no. S00313032+06911

Built
1963
62 years old
Condition
Good
inspected August 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
103 ft
2 main spans
Daily traffic
621
2023 count
Owner
State
State Highway Agency

About this bridge

IRR - S 313 over Soap Creek is a prestressed concrete stringer/multi-beam or girder carrying IRR - S 313 over Soap Creek in Big Horn County, Montana. It was built in 1963, so it is 62 years old, older 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 621 vehicles a day, roughly 7% of them trucks, projected to reach 652 by 2043. The structure is 103 ft (31.4 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
CrossesSoap Creek
Location9M SW ST Xavier
RouteState Highway 313
CountyBig Horn County
StateMontana
Coordinates45.37348, -107.79032
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 protection8 Very GoodNo problems noted.
Last inspectionAugust 2024
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 rating43.5 US tons
Inventory rating33.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length103 ft (31.4 m)
Longest span51 ft (15.5 m)
Deck width35 ft (10.8 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic621 (2023)
Projected traffic652 by 2043
Trucks7%
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 Soap Creek built?

It was built in 1963, making it 62 years old in 2025.

What condition is IRR - S 313 over Soap Creek 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 August 2024.

How much traffic does IRR - S 313 over Soap Creek carry?

About 621 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is IRR - S 313 over Soap Creek?

The structure is 103 ft (31.4 m) long with a longest span of 51 ft (15.5 m) and a deck 35 ft wide.

Who owns IRR - S 313 over Soap Creek?

It is owned by the State Highway Agency.