US Bridges

I 90 over Int Superior

Good

Mineral County, Montana · Superior · Structure no. I00090047+05521

Built
1960
65 years old
Condition
Good
inspected April 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
154 ft
3 main spans
Daily traffic
3,825
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over Int Superior is a prestressed concrete stringer/multi-beam or girder carrying I 90 over Int Superior in Mineral 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 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 3,825 vehicles a day, roughly 24% of them trucks, projected to reach 4,015 by 2043. The structure is 154 ft (46.9 m) long and 30 ft wide.

Location

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CarriesI 90
CrossesInt Superior
LocationSuperior
RouteInterstate 90
CountyMineral County
StateMontana
Coordinates47.19204, -114.8912
Functional classRural Principal Arterial - Interstate

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.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating49.1 US tons
Inventory rating38 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length154 ft (46.9 m)
Longest span61 ft (18.6 m)
Deck width30 ft (9 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,825 (2023)
Projected traffic4,015 by 2043
Trucks24%
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$405,000
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 90 over Int Superior built?

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

What condition is I 90 over Int Superior 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 April 2023.

How much traffic does I 90 over Int Superior carry?

About 3,825 vehicles per day (2023 count), of which roughly 24% are trucks.

How long is I 90 over Int Superior?

The structure is 154 ft (46.9 m) long with a longest span of 61 ft (18.6 m) and a deck 30 ft wide.

Who owns I 90 over Int Superior?

It is owned by the State Highway Agency.