US Bridges

Stc 6731;55th East over Harrison Canal

FairPosted for load

Bonneville County, Idaho · 2.3 N. 2 E. Ucon · Structure no. 000000000020890

Built
1961
64 years old
Condition
Fair
inspected November 2024
Type
Frame
Concrete
Length
22 ft
1 main span
Daily traffic
4,000
2023 count
Owner
County
County Highway Agency

About this bridge

Stc 6731;55th East over Harrison Canal is a concrete frame carrying Stc 6731;55th East over Harrison Canal in Bonneville County, Idaho. It was built in 1961, so it is 64 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 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 4,000 vehicles a day, roughly 8% of them trucks, projected to reach 6,000 by 2042. The structure is 22 ft (6.7 m) long and 55 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesStc 6731;55th East
CrossesHarrison Canal
Location2.3 N. 2 E. Ucon
RouteCounty Highway 6731
CountyBonneville County
StateIdaho
Coordinates43.62658, -111.92383
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating42 US tons
Inventory rating25 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length22 ft (6.7 m)
Longest span22 ft (6.7 m)
Deck width55 ft (16.9 m)
Roadway width33 ft (10.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,000 (2023)
Projected traffic6,000 by 2042
Trucks8%
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$468,000 (2018 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Stc 6731;55th East over Harrison Canal built?

It was built in 1961, making it 64 years old in 2025.

What condition is Stc 6731;55th East over Harrison 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 2024.

How much traffic does Stc 6731;55th East over Harrison Canal carry?

About 4,000 vehicles per day (2023 count), of which roughly 8% are trucks.

How long is Stc 6731;55th East over Harrison Canal?

The structure is 22 ft (6.7 m) long with a longest span of 22 ft (6.7 m) and a deck 55 ft wide.

Who owns Stc 6731;55th East over Harrison Canal?

It is owned by the County Highway Agency.