US Bridges

I 90 over Int Logan

Fair

Gallatin County, Montana · Logan · Structure no. I00090283+02651

Built
1963
62 years old
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
143 ft
3 main spans
Daily traffic
9,762
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over Int Logan is a prestressed concrete stringer/multi-beam or girder carrying I 90 over Int Logan in Gallatin County, Montana. It was built in 1963, so it is 62 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 9,762 vehicles a day, roughly 12% of them trucks, projected to reach 11,031 by 2043. The structure is 143 ft (43.6 m) long and 41 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 90
CrossesInt Logan
LocationLogan
RouteInterstate 90
CountyGallatin County
StateMontana
Coordinates45.88187, -111.43804
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating42 US tons
Inventory rating33 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length143 ft (43.6 m)
Longest span50 ft (15.2 m)
Deck width41 ft (12.5 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,762 (2023)
Projected traffic11,031 by 2043
Trucks12%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
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 Logan built?

It was built in 1963, making it 62 years old in 2025.

What condition is I 90 over Int Logan 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 November 2023.

How much traffic does I 90 over Int Logan carry?

About 9,762 vehicles per day (2023 count), of which roughly 12% are trucks.

How long is I 90 over Int Logan?

The structure is 143 ft (43.6 m) long with a longest span of 50 ft (15.2 m) and a deck 41 ft wide.

Who owns I 90 over Int Logan?

It is owned by the State Highway Agency.