US Bridges

Stc 3809;MIDDLE Fk over M.Fk.Boise River(kirby)

PoorPosted for load

Elmore County, Idaho · 0.1 N. 1.8 W. Atlanta · Structure no. 000000000027996

Built
1991
34 years old
Condition
Poor
inspected September 2024
Type
Truss - Deck
Steel
Length
137 ft
1 main span
Daily traffic
30
2023 count
Owner
Local
Other Local Agency

About this bridge

Stc 3809;MIDDLE Fk over M.Fk.Boise River(kirby) is a steel truss - deck carrying Stc 3809;MIDDLE Fk over M.Fk.Boise River(kirby) in Elmore County, Idaho. It was built in 1991, so it is 34 years old, younger than the Idaho average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for load restriction.

It carries about 30 vehicles a day, projected to reach 45 by 2042. The structure is 137 ft (41.8 m) long and 20 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesStc 3809;MIDDLE Fk
CrossesM.Fk.Boise River(kirby)
Location0.1 N. 1.8 W. Atlanta
RouteCounty Highway 3809
CountyElmore County
StateIdaho
Coordinates43.80283, -115.16253
Functional classRural Major Collector

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure8 Very GoodNo problems noted.
Channel and channel protection9 ExcellentNo problems noted.
Last inspectionSeptember 2024
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating35.1 US tons
Inventory rating21.1 US tons

Structure

Structure typeTruss - Deck
MaterialSteel
DeckOpen grating
Main spans1
Design loadHS 20
Structure length137 ft (41.8 m)
Longest span131 ft (39.9 m)
Deck width20 ft (6.1 m)
Roadway width19 ft (5.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30 (2023)
Projected traffic45 by 2042
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerOther Local Agency
Maintained byOther Local 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 Stc 3809;MIDDLE Fk over M.Fk.Boise River(kirby) built?

It was built in 1991, making it 34 years old in 2025.

What condition is Stc 3809;MIDDLE Fk over M.Fk.Boise River(kirby) in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in September 2024.

How much traffic does Stc 3809;MIDDLE Fk over M.Fk.Boise River(kirby) carry?

About 30 vehicles per day (2023 count).

How long is Stc 3809;MIDDLE Fk over M.Fk.Boise River(kirby)?

The structure is 137 ft (41.8 m) long with a longest span of 131 ft (39.9 m) and a deck 20 ft wide.

Who owns Stc 3809;MIDDLE Fk over M.Fk.Boise River(kirby)?

It is owned by the Other Local Agency.