US Bridges

Seiad Creek Road over Seiad Creek

Fair

Siskiyou County, California · Horse · Structure no. 050551000001041

Built
1959
66 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Concrete
Length
70 ft
3 main spans
Daily traffic
50
Owner
Federal
U.S. Forest Service

About this bridge

Seiad Creek Road over Seiad Creek is a concrete stringer/multi-beam or girder carrying Seiad Creek Road over Seiad Creek in Siskiyou County, California. It was built in 1959, so it is 66 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 70 ft (21.3 m) long and 19 ft wide.

Location

Open in Google Maps
CarriesSeiad Creek Road
CrossesSeiad Creek
LocationHorse
RouteFederal Lands Road 48N20
CountySiskiyou County
StateCalifornia
Coordinates41.90529, -123.14201
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 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation*: *
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating—
Inventory rating—

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length70 ft (21.3 m)
Longest span40 ft (12.2 m)
Deck width19 ft (5.9 m)
Roadway width17 ft (5.2 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 closed—
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was Seiad Creek Road over Seiad Creek built?

It was built in 1959, making it 66 years old in 2025.

What condition is Seiad Creek Road over Seiad 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 2024.

How much traffic does Seiad Creek Road over Seiad Creek carry?

About 50 vehicles per day (latest count).

How long is Seiad Creek Road over Seiad Creek?

The structure is 70 ft (21.3 m) long with a longest span of 40 ft (12.2 m) and a deck 19 ft wide.

Who owns Seiad Creek Road over Seiad Creek?

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