US Bridges

Road 20N05 over Eel River

Fair

Mendocino County, California · 38 Mi. West of Elk Creek · Structure no. 050854000001005

Built
1981
44 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Concrete
Length
80 ft
1 main span
Daily traffic
5
1992 count
Owner
Federal
U.S. Forest Service

About this bridge

Road 20N05 over Eel River is a concrete stringer/multi-beam or girder carrying Road 20N05 over Eel River in Mendocino County, California. It was built in 1981, so it is 44 years old, younger 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 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 5 vehicles a day, projected to reach 7 by 2045. The structure is 80 ft (24.4 m) long and 19 ft wide. If it were closed, the detour would be 2.5 mi (4 km).

Location

Open in Google Maps
CarriesRoad 20N05
CrossesEel River
Location38 Mi. West of Elk Creek
RouteFederal Lands Road 20N00
CountyMendocino County
StateCalifornia
Coordinates39.58253, -122.91801
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
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 inspectionAugust 2023
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
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 alignment4: Meets minimum tolerable limits to be left in place as is
Operating rating50.7 US tons
Inventory rating38.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete
DeckConcrete, precast panels
Main spans1 (+1 approach)
Design loadHS 20
Structure length80 ft (24.4 m)
Longest span65 ft (19.8 m)
Deck width19 ft (5.7 m)
Roadway width18 ft (5.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5 (1992)
Projected traffic7 by 2045
Trucks—
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed2.5 mi (4 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerU.S. Forest Service
Maintained byU.S. Forest Service
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Road 20N05 over Eel River built?

It was built in 1981, making it 44 years old in 2025.

What condition is Road 20N05 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 2023.

How much traffic does Road 20N05 over Eel River carry?

About 5 vehicles per day (1992 count).

How long is Road 20N05 over Eel River?

The structure is 80 ft (24.4 m) long with a longest span of 65 ft (19.8 m) and a deck 19 ft wide.

Who owns Road 20N05 over Eel River?

It is owned by the U.S. Forest Service.