US Bridges

81st North Road over Idaho Canal

Fair

Bonneville County, Idaho · 5.3 N. 0.5 E. Idaho Falls · Structure no. 000000000031110

Built
1966
59 years old
Condition
Fair
inspected November 2023
Type
Tee Beam
Prestressed Concrete
Length
85 ft
2 main spans
Daily traffic
490
2023 count
Owner
County
County Highway Agency

About this bridge

81st North Road over Idaho Canal is a prestressed concrete tee beam carrying 81st North Road over Idaho Canal in Bonneville County, Idaho. It was built in 1966, so it is 59 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 490 vehicles a day, roughly 7% of them trucks, projected to reach 735 by 2042. The structure is 85 ft (25.9 m) long and 27 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries81st North Road
CrossesIdaho Canal
Location5.3 N. 0.5 E. Idaho Falls
RouteCounty Highway 0
CountyBonneville County
StateIdaho
Coordinates43.56825, -112.02858
Functional classRural Local

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 protection7 GoodSome minor problems.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating38 US tons
Inventory rating23 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadH 15
Structure length85 ft (25.9 m)
Longest span42 ft (12.8 m)
Deck width27 ft (8.3 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic490 (2023)
Projected traffic735 by 2042
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$769,000 (2017 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was 81st North Road over Idaho Canal built?

It was built in 1966, making it 59 years old in 2025.

What condition is 81st North Road over Idaho Canal 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 81st North Road over Idaho Canal carry?

About 490 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is 81st North Road over Idaho Canal?

The structure is 85 ft (25.9 m) long with a longest span of 42 ft (12.8 m) and a deck 27 ft wide.

Who owns 81st North Road over Idaho Canal?

It is owned by the County Highway Agency.