US Bridges

I 15 over Int Shelby-Rr

Fair

Toole County, Montana · Shelby · Structure no. I00015363+04831

Built
1960
65 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
429 ft
2 main spans
Daily traffic
1,021
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 over Int Shelby-Rr is a steel stringer/multi-beam or girder carrying I 15 over Int Shelby-Rr in Toole County, Montana. It was built in 1960, so it is 65 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 1,021 vehicles a day, roughly 37% of them trucks, projected to reach 1,071 by 2043. The structure is 429 ft (130.7 m) long and 44 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 15
CrossesInt Shelby-Rr
LocationShelby
RouteInterstate 15
CountyToole County
StateMontana
Coordinates48.51567, -111.87613
Functional classRural Principal Arterial - Interstate

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating39.2 US tons
Inventory rating29.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2 (+6 approach)
Design loadHS 20
Structure length429 ft (130.7 m)
Longest span68 ft (20.6 m)
Deck width44 ft (13.4 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,021 (2023)
Projected traffic1,071 by 2043
Trucks37%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway and railroad
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 15 over Int Shelby-Rr built?

It was built in 1960, making it 65 years old in 2025.

What condition is I 15 over Int Shelby-Rr 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 I 15 over Int Shelby-Rr carry?

About 1,021 vehicles per day (2023 count), of which roughly 37% are trucks.

How long is I 15 over Int Shelby-Rr?

The structure is 429 ft (130.7 m) long with a longest span of 68 ft (20.6 m) and a deck 44 ft wide.

Who owns I 15 over Int Shelby-Rr?

It is owned by the State Highway Agency.