US Bridges

I 15 over Int Bernice-Boulder R RD

Fair

Jefferson County, Montana · 5M S Basin · Structure no. I00015151+07342

Built
1985
40 years old
Condition
Fair
inspected January 2025
Type
Stringer/Multi-beam or Girder
Steel
Length
147 ft
3 main spans
Daily traffic
1,591
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 over Int Bernice-Boulder R RD is a steel stringer/multi-beam or girder carrying I 15 over Int Bernice-Boulder R RD in Jefferson County, Montana. It was built in 1985, so it is 40 years old, younger 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 5 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 1,591 vehicles a day, roughly 16% of them trucks, projected to reach 1,718 by 2043. The structure is 147 ft (44.8 m) long and 40 ft wide.

Location

Open in Google Maps
CarriesI 15
CrossesInt Bernice-Boulder R RD
Location5M S Basin
RouteInterstate 15
CountyJefferson County
StateMontana
Coordinates46.25827, -112.34152
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment7: Better than present minimum criteria
Operating rating59.3 US tons
Inventory rating45.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length147 ft (44.8 m)
Longest span50 ft (15.2 m)
Deck width40 ft (12.3 m)
Roadway width37 ft (11.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,591 (2023)
Projected traffic1,718 by 2043
Trucks16%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed—
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 Bernice-Boulder R RD built?

It was built in 1985, making it 40 years old in 2025.

What condition is I 15 over Int Bernice-Boulder R RD 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 January 2025.

How much traffic does I 15 over Int Bernice-Boulder R RD carry?

About 1,591 vehicles per day (2023 count), of which roughly 16% are trucks.

How long is I 15 over Int Bernice-Boulder R RD?

The structure is 147 ft (44.8 m) long with a longest span of 50 ft (15.2 m) and a deck 40 ft wide.

Who owns I 15 over Int Bernice-Boulder R RD?

It is owned by the State Highway Agency.