US Bridges

U.S. Highway 101 over Strongs Creek

Fair

Humboldt County, California · 01-HUM-101-59.94 · Structure no. 04 0107

Built
1962
63 years old
Condition
Fair
inspected July 2023
Type
Culvert
Concrete
Length
40 ft
1 main span
Daily traffic
13,000
2009 count
Owner
State
State Highway Agency

About this bridge

U.S. Highway 101 over Strongs Creek is a concrete culvert carrying U.S. Highway 101 over Strongs Creek in Humboldt County, California. It was built in 1962, so it is 63 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 13,000 vehicles a day, roughly 10% of them trucks, projected to reach 27,041 by 2041. The structure is 40 ft (12.2 m) long and 89 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesU.S. Highway 101
CrossesStrongs Creek
Location01-HUM-101-59.94
RouteU.S. Route 101
CountyHumboldt County
StateCalifornia
Coordinates40.58072, -124.1506
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating77.2 US tons
Inventory rating46.4 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length40 ft (12.2 m)
Longest span39 ft (11.9 m)
Deck width89 ft (27 m)
Roadway width86 ft (26.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,000 (2009)
Projected traffic27,041 by 2041
Trucks10%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 U.S. Highway 101 over Strongs Creek built?

It was built in 1962, making it 63 years old in 2025.

What condition is U.S. Highway 101 over Strongs 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 July 2023.

How much traffic does U.S. Highway 101 over Strongs Creek carry?

About 13,000 vehicles per day (2009 count), of which roughly 10% are trucks.

How long is U.S. Highway 101 over Strongs Creek?

The structure is 40 ft (12.2 m) long with a longest span of 39 ft (11.9 m) and a deck 89 ft wide.

Who owns U.S. Highway 101 over Strongs Creek?

It is owned by the State Highway Agency.