US Bridges

I 15 over Int Harrison Ave

Fair

Silver Bow County, Montana · Butte · Structure no. I00015127+09362

Built
1960
65 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
209 ft
4 main spans
Daily traffic
7,009
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 over Int Harrison Ave is a prestressed concrete stringer/multi-beam or girder carrying I 15 over Int Harrison Ave in Silver Bow 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 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 7,009 vehicles a day, roughly 15% of them trucks, projected to reach 7,499 by 2043. The structure is 209 ft (63.7 m) long and 44 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesI 15
CrossesInt Harrison Ave
LocationButte
RouteInterstate 15
CountySilver Bow County
StateMontana
Coordinates45.98444, -112.50817
Functional classUrban 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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionSeptember 2023
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 geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment6: Equal to present minimum criteria
Operating rating70 US tons
Inventory rating54 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length209 ft (63.7 m)
Longest span61 ft (18.6 m)
Deck width44 ft (13.3 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,009 (2023)
Projected traffic7,499 by 2043
Trucks15%
Lanes on structure3
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed8.1 mi (13 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$815,000
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 15 over Int Harrison Ave built?

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

What condition is I 15 over Int Harrison Ave 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 September 2023.

How much traffic does I 15 over Int Harrison Ave carry?

About 7,009 vehicles per day (2023 count), of which roughly 15% are trucks.

How long is I 15 over Int Harrison Ave?

The structure is 209 ft (63.7 m) long with a longest span of 61 ft (18.6 m) and a deck 44 ft wide.

Who owns I 15 over Int Harrison Ave?

It is owned by the State Highway Agency.