US Bridges

Cockrobin Isld RD over Eel River

Fair

Humboldt County, California · 0.5 MI S of Cannibal RD · Structure no. 04C0098

Built
1961
64 years old
Condition
Fair
inspected August 2024
Type
Box Beam or Girders - Single or Spread
Concrete Continuous
Length
776 ft
8 main spans
Daily traffic
25
2014 count
Owner
County
County Highway Agency

About this bridge

Cockrobin Isld RD over Eel River is a concrete continuous box beam or girders - single or spread carrying Cockrobin Isld RD over Eel River in Humboldt County, California. It was built in 1961, so it is 64 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 25 vehicles a day, roughly 1% of them trucks, projected to reach 51 by 2041. The structure is 776 ft (236.5 m) long and 12 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

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CarriesCockrobin Isld RD
CrossesEel River
Location0.5 MI S of Cannibal RD
RouteCounty Highway 0
CountyHumboldt County
StateCalifornia
Coordinates40.6354, -124.28145
Functional classRural Local

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 protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating43.5 US tons
Inventory rating33.6 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans8
Design loadH 20
Structure length776 ft (236.5 m)
Longest span106 ft (32.2 m)
Deck width12 ft (3.7 m)
Roadway width10 ft (3.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic25 (2014)
Projected traffic51 by 2041
Trucks1%
Lanes on structure1
Traffic directionOne-lane bridge for two-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 Cockrobin Isld RD over Eel River built?

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

What condition is Cockrobin Isld RD over Eel 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 August 2024.

How much traffic does Cockrobin Isld RD over Eel River carry?

About 25 vehicles per day (2014 count), of which roughly 1% are trucks.

How long is Cockrobin Isld RD over Eel River?

The structure is 776 ft (236.5 m) long with a longest span of 106 ft (32.2 m) and a deck 12 ft wide.

Who owns Cockrobin Isld RD over Eel River?

It is owned by the County Highway Agency.