US Bridges

SH 81 over J Canal

Fair

Cassia County, Idaho · 2.8 E. Declo · Structure no. 000000000016606

Built
2006
19 years old
Condition
Fair
inspected March 2021
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
58 ft
1 main span
Daily traffic
1,300
2023 count
Owner
State
State Highway Agency

About this bridge

SH 81 over J Canal is a prestressed concrete box beam or girders - multiple carrying SH 81 over J Canal in Cassia County, Idaho. It was built in 2006, so it is 19 years old, younger 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 1,300 vehicles a day, roughly 29% of them trucks, projected to reach 1,950 by 2042. The structure is 58 ft (17.7 m) long and 44 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesSH 81
CrossesJ Canal
Location2.8 E. Declo
RouteState Highway 81
CountyCassia County
StateIdaho
Coordinates42.52606, -113.57808
Functional classRural Major Collector

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.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMarch 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating94 US tons
Inventory rating41 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHL 93
Structure length58 ft (17.7 m)
Longest span55 ft (16.8 m)
Deck width44 ft (13.4 m)
Roadway width41 ft (12.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,300 (2023)
Projected traffic1,950 by 2042
Trucks29%
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

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 SH 81 over J Canal built?

It was built in 2006, making it 19 years old in 2025.

What condition is SH 81 over J 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 March 2021.

How much traffic does SH 81 over J Canal carry?

About 1,300 vehicles per day (2023 count), of which roughly 29% are trucks.

How long is SH 81 over J Canal?

The structure is 58 ft (17.7 m) long with a longest span of 55 ft (16.8 m) and a deck 44 ft wide.

Who owns SH 81 over J Canal?

It is owned by the State Highway Agency.