US Bridges

STC9123;ALLUMBAUGH over Ridenbaugh Canal

Fair

Ada County, Idaho · In Boise;allumbaugh St. · Structure no. 000000000025725

Built
1971
54 years old
Condition
Fair
inspected March 2021
Type
Tee Beam
Prestressed Concrete
Length
27 ft
1 main span
Daily traffic
1,300
2023 count
Owner
County
County Highway Agency

About this bridge

STC9123;ALLUMBAUGH over Ridenbaugh Canal is a prestressed concrete tee beam carrying STC9123;ALLUMBAUGH over Ridenbaugh Canal in Ada County, Idaho. It was built in 1971, so it is 54 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 1,300 vehicles a day, roughly 16% of them trucks, projected to reach 1,950 by 2042. The structure is 27 ft (8.2 m) long and 36 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesSTC9123;ALLUMBAUGH
CrossesRidenbaugh Canal
LocationIn Boise;allumbaugh St.
RouteCity Street 9123
CountyAda County
StateIdaho
Coordinates43.60481, -116.2663
Functional classUrban 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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
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 evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating49.6 US tons
Inventory rating36.7 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length27 ft (8.2 m)
Longest span26 ft (7.9 m)
Deck width36 ft (11 m)
Roadway width29 ft (8.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,300 (2023)
Projected traffic1,950 by 2042
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 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$675,000 (2021 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was STC9123;ALLUMBAUGH over Ridenbaugh Canal built?

It was built in 1971, making it 54 years old in 2025.

What condition is STC9123;ALLUMBAUGH over Ridenbaugh 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 STC9123;ALLUMBAUGH over Ridenbaugh Canal carry?

About 1,300 vehicles per day (2023 count), of which roughly 16% are trucks.

How long is STC9123;ALLUMBAUGH over Ridenbaugh Canal?

The structure is 27 ft (8.2 m) long with a longest span of 26 ft (7.9 m) and a deck 36 ft wide.

Who owns STC9123;ALLUMBAUGH over Ridenbaugh Canal?

It is owned by the County Highway Agency.