US Bridges

I 90 over St. Regis Rvr-Int Ramp

Fair

Mineral County, Montana · St. Regis · Structure no. I00090033+05283

Built
1983
42 years old
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
261 ft
3 main spans
Daily traffic
1,321
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over St. Regis Rvr-Int Ramp is a prestressed concrete stringer/multi-beam or girder carrying I 90 over St. Regis Rvr-Int Ramp in Mineral County, Montana. It was built in 1983, so it is 42 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 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 1,321 vehicles a day, roughly 3% of them trucks, projected to reach 1,413 by 2043. The structure is 261 ft (79.5 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
CrossesSt. Regis Rvr-Int Ramp
LocationSt. Regis
RouteInterstate 90
CountyMineral County
StateMontana
Coordinates47.29536, -115.09874
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating75.9 US tons
Inventory rating43 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length261 ft (79.5 m)
Longest span85 ft (25.9 m)
Deck width41 ft (12.4 m)
Roadway width37 ft (11.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,321 (2023)
Projected traffic1,413 by 2043
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was I 90 over St. Regis Rvr-Int Ramp built?

It was built in 1983, making it 42 years old in 2025.

What condition is I 90 over St. Regis Rvr-Int Ramp 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 2023.

How much traffic does I 90 over St. Regis Rvr-Int Ramp carry?

About 1,321 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is I 90 over St. Regis Rvr-Int Ramp?

The structure is 261 ft (79.5 m) long with a longest span of 85 ft (25.9 m) and a deck 41 ft wide.

Who owns I 90 over St. Regis Rvr-Int Ramp?

It is owned by the State Highway Agency.