US Bridges

IRR - I 90 over Sarpy Road-S 384

Fair

Big Horn County, Montana · 1.2M E Hardin · Structure no. I00090498+07331

Built
1971
54 years old
Condition
Fair
inspected July 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
120 ft
3 main spans
Daily traffic
4,258
2023 count
Owner
State
State Highway Agency

About this bridge

IRR - I 90 over Sarpy Road-S 384 is a prestressed concrete stringer/multi-beam or girder carrying IRR - I 90 over Sarpy Road-S 384 in Big Horn 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 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 4,258 vehicles a day, roughly 18% of them trucks, projected to reach 4,471 by 2043. The structure is 120 ft (36.6 m) long and 44 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesIRR - I 90
CrossesSarpy Road-S 384
Location1.2M E Hardin
RouteInterstate 90
CountyBig Horn County
StateMontana
Coordinates45.73086, -107.56331
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.
Last inspectionJuly 2024
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 rating52 US tons
Inventory rating37 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length120 ft (36.6 m)
Longest span47 ft (14.3 m)
Deck width44 ft (13.5 m)
Roadway width41 ft (12.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,258 (2023)
Projected traffic4,471 by 2043
Trucks18%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was IRR - I 90 over Sarpy Road-S 384 built?

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

What condition is IRR - I 90 over Sarpy Road-S 384 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 July 2024.

How much traffic does IRR - I 90 over Sarpy Road-S 384 carry?

About 4,258 vehicles per day (2023 count), of which roughly 18% are trucks.

How long is IRR - I 90 over Sarpy Road-S 384?

The structure is 120 ft (36.6 m) long with a longest span of 47 ft (14.3 m) and a deck 44 ft wide.

Who owns IRR - I 90 over Sarpy Road-S 384?

It is owned by the State Highway Agency.