US Bridges

I 90 over Int Warm Springs

Good

Deer Lodge County, Montana · Warm Springs · Structure no. I00090201+05491

Built
1978
47 years old
Condition
Good
inspected October 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
226 ft
4 main spans
Daily traffic
5,209
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over Int Warm Springs is a prestressed concrete stringer/multi-beam or girder carrying I 90 over Int Warm Springs in Deer Lodge County, Montana. It was built in 1978, so it is 47 years old, younger than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 5,209 vehicles a day, roughly 24% of them trucks, projected to reach 5,599 by 2043. The structure is 226 ft (68.8 m) long and 44 ft wide.

Location

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CarriesI 90
CrossesInt Warm Springs
LocationWarm Springs
RouteInterstate 90
CountyDeer Lodge County
StateMontana
Coordinates46.18157, -112.78396
Functional classRural Principal Arterial - Interstate

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 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 geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating53 US tons
Inventory rating29 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length226 ft (68.8 m)
Longest span70 ft (21.3 m)
Deck width44 ft (13.5 m)
Roadway width41 ft (12.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,209 (2023)
Projected traffic5,599 by 2043
Trucks24%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway and waterway
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was I 90 over Int Warm Springs built?

It was built in 1978, making it 47 years old in 2025.

What condition is I 90 over Int Warm Springs in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in October 2023.

How much traffic does I 90 over Int Warm Springs carry?

About 5,209 vehicles per day (2023 count), of which roughly 24% are trucks.

How long is I 90 over Int Warm Springs?

The structure is 226 ft (68.8 m) long with a longest span of 70 ft (21.3 m) and a deck 44 ft wide.

Who owns I 90 over Int Warm Springs?

It is owned by the State Highway Agency.