US Bridges

Alderpoint Road over Cooper Creek

Fair

Humboldt County, California · 30.4 MI E/N S.H. 101 · Structure no. 04C0166

Built
1952
73 years old
Condition
Fair
inspected February 2024
Type
Slab
Concrete
Length
28 ft
1 main span
Daily traffic
250
2008 count
Owner
County
County Highway Agency

About this bridge

Alderpoint Road over Cooper Creek is a concrete slab carrying Alderpoint Road over Cooper Creek in Humboldt County, California. It was built in 1952, so it is 73 years old, older than the California average of 54.8 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.

It carries about 250 vehicles a day, roughly 5% of them trucks, projected to reach 327 by 2042. The structure is 28 ft (8.5 m) long and 24 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesAlderpoint Road
CrossesCooper Creek
Location30.4 MI E/N S.H. 101
RouteCounty Highway 0
CountyHumboldt County
StateCalifornia
Coordinates40.30958, -123.65562
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
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 adequacy7: Better than present minimum criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating20.4 US tons
Inventory rating15.8 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length28 ft (8.5 m)
Longest span27 ft (8.2 m)
Deck width24 ft (7.4 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic250 (2008)
Projected traffic327 by 2042
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Alderpoint Road over Cooper Creek built?

It was built in 1952, making it 73 years old in 2025.

What condition is Alderpoint Road over Cooper Creek 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 February 2024.

How much traffic does Alderpoint Road over Cooper Creek carry?

About 250 vehicles per day (2008 count), of which roughly 5% are trucks.

How long is Alderpoint Road over Cooper Creek?

The structure is 28 ft (8.5 m) long with a longest span of 27 ft (8.2 m) and a deck 24 ft wide.

Who owns Alderpoint Road over Cooper Creek?

It is owned by the County Highway Agency.