US Bridges

Road 21N02 over Sulphur Creek

Fair

Plumas County, California · Sulphur Creek · Structure no. 051151000001029

Built
1964
61 years old
Condition
Fair
inspected September 2023
Type
Frame
Concrete
Length
31 ft
1 main span
Daily traffic
50
Owner
Federal
U.S. Forest Service

About this bridge

Road 21N02 over Sulphur Creek is a concrete frame carrying Road 21N02 over Sulphur Creek in Plumas County, California. It was built in 1964, so it is 61 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 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 50 vehicles a day, projected to reach 75 by 2045. The structure is 31 ft (9.3 m) long and 16 ft wide. If it were closed, the detour would be 2.5 mi (4 km).

Location

Open in Google Maps
CarriesRoad 21N02
CrossesSulphur Creek
LocationSulphur Creek
RouteFederal Lands Road 21N02
CountyPlumas County
StateCalifornia
Coordinates39.70721, -120.53198
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being 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 rating61.1 US tons
Inventory rating47.2 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length31 ft (9.3 m)
Longest span26 ft (8 m)
Deck width16 ft (5 m)
Roadway width14 ft (4.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (—)
Projected traffic75 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Road 21N02 over Sulphur Creek built?

It was built in 1964, making it 61 years old in 2025.

What condition is Road 21N02 over Sulphur 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 September 2023.

How much traffic does Road 21N02 over Sulphur Creek carry?

About 50 vehicles per day (latest count).

How long is Road 21N02 over Sulphur Creek?

The structure is 31 ft (9.3 m) long with a longest span of 26 ft (8 m) and a deck 16 ft wide.

Who owns Road 21N02 over Sulphur Creek?

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