US Bridges

I 90 over Sep Fort Ellis Road

Fair

Gallatin County, Montana · 1.2M E Bozeman · Structure no. I00090310+09782

Built
1971
54 years old
Condition
Fair
inspected May 2024
Type
Slab
Concrete Continuous
Length
79 ft
3 main spans
Daily traffic
9,819
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over Sep Fort Ellis Road is a concrete continuous slab carrying I 90 over Sep Fort Ellis Road in Gallatin County, Montana. It was built in 1971, so it is 54 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 9,819 vehicles a day, roughly 13% of them trucks, projected to reach 10,702 by 2043. The structure is 79 ft (24.1 m) long and 44 ft wide.

Location

Open in Google Maps
CarriesI 90
CrossesSep Fort Ellis Road
Location1.2M E Bozeman
RouteInterstate 90
CountyGallatin County
StateMontana
Coordinates45.66636, -110.98029
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2024
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 geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating54 US tons
Inventory rating41 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length79 ft (24.1 m)
Longest span30 ft (9.1 m)
Deck width44 ft (13.5 m)
Roadway width41 ft (12.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,819 (2023)
Projected traffic10,702 by 2043
Trucks13%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
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 90 over Sep Fort Ellis Road built?

It was built in 1971, making it 54 years old in 2025.

What condition is I 90 over Sep Fort Ellis Road 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 May 2024.

How much traffic does I 90 over Sep Fort Ellis Road carry?

About 9,819 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is I 90 over Sep Fort Ellis Road?

The structure is 79 ft (24.1 m) long with a longest span of 30 ft (9.1 m) and a deck 44 ft wide.

Who owns I 90 over Sep Fort Ellis Road?

It is owned by the State Highway Agency.