US Bridges

I 90 over Sep Eastside Road

Fair

Powell County, Montana · 0.6M S Deer Lodge · Structure no. I00090187+00292

Built
1974
51 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
143 ft
3 main spans
Daily traffic
4,371
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over Sep Eastside Road is a prestressed concrete stringer/multi-beam or girder carrying I 90 over Sep Eastside Road in Powell County, Montana. It was built in 1974, so it is 51 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 4,371 vehicles a day, roughly 24% of them trucks, projected to reach 4,720 by 2043. The structure is 143 ft (43.6 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 90
CrossesSep Eastside Road
Location0.6M S Deer Lodge
RouteInterstate 90
CountyPowell County
StateMontana
Coordinates46.38284, -112.72562
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 inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59 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 span66 ft (20.1 m)
Deck width44 ft (13.5 m)
Roadway width41 ft (12.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,371 (2023)
Projected traffic4,720 by 2043
Trucks24%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
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 proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 90 over Sep Eastside Road built?

It was built in 1974, making it 51 years old in 2025.

What condition is I 90 over Sep Eastside 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 August 2023.

How much traffic does I 90 over Sep Eastside Road carry?

About 4,371 vehicles per day (2023 count), of which roughly 24% are trucks.

How long is I 90 over Sep Eastside Road?

The structure is 143 ft (43.6 m) long with a longest span of 66 ft (20.1 m) and a deck 44 ft wide.

Who owns I 90 over Sep Eastside Road?

It is owned by the State Highway Agency.