US Bridges

I 15 over Int Grasshopper Creek

Fair

Beaverhead County, Montana · 8M N Clark Canyon Dam · Structure no. I00015052+06211

Built
1988
37 years old
Condition
Fair
inspected December 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
125 ft
3 main spans
Daily traffic
2,239
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 over Int Grasshopper Creek is a prestressed concrete stringer/multi-beam or girder carrying I 15 over Int Grasshopper Creek in Beaverhead County, Montana. It was built in 1988, so it is 37 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 2,239 vehicles a day, roughly 24% of them trucks, projected to reach 2,395 by 2043. The structure is 125 ft (38.1 m) long and 40 ft wide.

Location

Open in Google Maps
CarriesI 15
CrossesInt Grasshopper Creek
Location8M N Clark Canyon Dam
RouteInterstate 15
CountyBeaverhead County
StateMontana
Coordinates45.09797, -112.77819
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating52 US tons
Inventory rating25 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length125 ft (38.1 m)
Longest span51 ft (15.6 m)
Deck width40 ft (12.3 m)
Roadway width38 ft (11.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,239 (2023)
Projected traffic2,395 by 2043
Trucks24%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 15 over Int Grasshopper Creek built?

It was built in 1988, making it 37 years old in 2025.

What condition is I 15 over Int Grasshopper Creek 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 December 2023.

How much traffic does I 15 over Int Grasshopper Creek carry?

About 2,239 vehicles per day (2023 count), of which roughly 24% are trucks.

How long is I 15 over Int Grasshopper Creek?

The structure is 125 ft (38.1 m) long with a longest span of 51 ft (15.6 m) and a deck 40 ft wide.

Who owns I 15 over Int Grasshopper Creek?

It is owned by the State Highway Agency.