US Bridges

I 90 over Int E Garrison-Rr

Fair

Powell County, Montana · 1.2M S Garrison · Structure no. I00090175+05332

Built
1979
46 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
582 ft
5 main spans
Daily traffic
5,232
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over Int E Garrison-Rr is a steel continuous stringer/multi-beam or girder carrying I 90 over Int E Garrison-Rr in Powell County, Montana. It was built in 1979, so it is 46 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 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 5,232 vehicles a day, roughly 20% of them trucks, projected to reach 5,650 by 2043. The structure is 582 ft (177.3 m) long and 44 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI 90
CrossesInt E Garrison-Rr
Location1.2M S Garrison
RouteInterstate 90
CountyPowell County
StateMontana
Coordinates46.51398, -112.79
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 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 rating41.4 US tons
Inventory rating32.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length582 ft (177.3 m)
Longest span148 ft (45.1 m)
Deck width44 ft (13.4 m)
Roadway width41 ft (12.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,232 (2023)
Projected traffic5,650 by 2043
Trucks20%
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 90 over Int E Garrison-Rr built?

It was built in 1979, making it 46 years old in 2025.

What condition is I 90 over Int E Garrison-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 September 2024.

How much traffic does I 90 over Int E Garrison-Rr carry?

About 5,232 vehicles per day (2023 count), of which roughly 20% are trucks.

How long is I 90 over Int E Garrison-Rr?

The structure is 582 ft (177.3 m) long with a longest span of 148 ft (45.1 m) and a deck 44 ft wide.

Who owns I 90 over Int E Garrison-Rr?

It is owned by the State Highway Agency.