US Bridges

I 90 over St. Regis Rvr-Int Ramp

Fair

Mineral County, Montana · 3.7M W St. Regis · Structure no. I00090030+02024

Built
1981
44 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
152 ft
2 main spans
Daily traffic
22
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 1981, so it is 44 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 22 vehicles a day, roughly 3% of them trucks, projected to reach 23 by 2043. The structure is 152 ft (46.2 m) long and 31 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
Location3.7M W St. Regis
RouteInterstate 90
CountyMineral County
StateMontana
Coordinates47.29591, -115.1638
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating53 US tons
Inventory rating27 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length152 ft (46.2 m)
Longest span76 ft (23.2 m)
Deck width31 ft (9.5 m)
Roadway width28 ft (8.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic22 (2023)
Projected traffic23 by 2043
Trucks3%
Lanes on structure1
Traffic directionOne-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 1981, making it 44 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 September 2023.

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

About 22 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 152 ft (46.2 m) long with a longest span of 76 ft (23.2 m) and a deck 31 ft wide.

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

It is owned by the State Highway Agency.