US Bridges

I 15 Nbl over Blackfoot River

Fair

Bingham County, Idaho · 2.2 S. Blackfoot · Structure no. 000000000011450

Built
1962
63 years old
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
155 ft
3 main spans
Daily traffic
12,500
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 Nbl over Blackfoot River is a prestressed concrete stringer/multi-beam or girder carrying I 15 Nbl over Blackfoot River in Bingham County, Idaho. It was built in 1962, so it is 63 years old, older than the Idaho average of 45.3 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 12,500 vehicles a day, roughly 20% of them trucks, projected to reach 18,750 by 2042. The structure is 155 ft (47.2 m) long and 40 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 15 Nbl
CrossesBlackfoot River
Location2.2 S. Blackfoot
RouteInterstate 15
CountyBingham County
StateIdaho
Coordinates43.17167, -112.386
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating65 US tons
Inventory rating39 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length155 ft (47.2 m)
Longest span49 ft (14.9 m)
Deck width40 ft (12.2 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic12,500 (2023)
Projected traffic18,750 by 2042
Trucks20%
Lanes on structure2
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 statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was I 15 Nbl over Blackfoot River built?

It was built in 1962, making it 63 years old in 2025.

What condition is I 15 Nbl over Blackfoot River 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 November 2023.

How much traffic does I 15 Nbl over Blackfoot River carry?

About 12,500 vehicles per day (2023 count), of which roughly 20% are trucks.

How long is I 15 Nbl over Blackfoot River?

The structure is 155 ft (47.2 m) long with a longest span of 49 ft (14.9 m) and a deck 40 ft wide.

Who owns I 15 Nbl over Blackfoot River?

It is owned by the State Highway Agency.