US Bridges

Stc 6749;2500N over Big Lost River

Fair

Butte County, Idaho · 1.4 W. 0.1 N. Arco · Structure no. 000000000031520

Built
1926
99 years old
Condition
Fair
inspected July 2023
Type
Tee Beam
Concrete
Length
36 ft
1 main span
Daily traffic
500
2023 count
Owner
County
County Highway Agency

About this bridge

Stc 6749;2500N over Big Lost River is a concrete tee beam carrying Stc 6749;2500N over Big Lost River in Butte County, Idaho. It was built in 1926, so it is 99 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 500 vehicles a day, roughly 22% of them trucks, projected to reach 750 by 2042. The structure is 36 ft (11 m) long and 26 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesStc 6749;2500N
CrossesBig Lost River
Location1.4 W. 0.1 N. Arco
RouteCounty Highway 6749
CountyButte County
StateIdaho
Coordinates43.63822, -113.32658
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
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 rating47 US tons
Inventory rating28 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length36 ft (11 m)
Longest span34 ft (10.4 m)
Deck width26 ft (7.9 m)
Roadway width23 ft (7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic500 (2023)
Projected traffic750 by 2042
Trucks22%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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$431,000 (2019 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Stc 6749;2500N over Big Lost River built?

It was built in 1926, making it 99 years old in 2025.

What condition is Stc 6749;2500N over Big Lost River 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 July 2023.

How much traffic does Stc 6749;2500N over Big Lost River carry?

About 500 vehicles per day (2023 count), of which roughly 22% are trucks.

How long is Stc 6749;2500N over Big Lost River?

The structure is 36 ft (11 m) long with a longest span of 34 ft (10.4 m) and a deck 26 ft wide.

Who owns Stc 6749;2500N over Big Lost River?

It is owned by the County Highway Agency.