US Bridges

U.S. Highway 101 over Maple Hill RD Salmon Crk

Fair

Humboldt County, California · 01-HUM-101-23.89 · Structure no. 04 0176

Built
1962
63 years old
Condition
Fair
inspected September 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
279 ft
3 main spans
Daily traffic
5,100
2014 count
Owner
State
State Highway Agency

About this bridge

U.S. Highway 101 over Maple Hill RD Salmon Crk is a concrete continuous box beam or girders - multiple carrying U.S. Highway 101 over Maple Hill RD Salmon Crk 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 5,100 vehicles a day, roughly 16% of them trucks, projected to reach 6,892 by 2041. The structure is 279 ft (85 m) long and 62 ft wide. If it were closed, the detour would be 39.1 mi (63 km).

Location

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CarriesU.S. Highway 101
CrossesMaple Hill RD Salmon Crk
Location01-HUM-101-23.89
RouteU.S. Route 101
CountyHumboldt County
StateCalifornia
Coordinates40.23488, -123.83317
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2024
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating53.2 US tons
Inventory rating38.3 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length279 ft (85 m)
Longest span105 ft (32 m)
Deck width62 ft (18.9 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,100 (2014)
Projected traffic6,892 by 2041
Trucks16%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway and waterway
Detour if closed39.1 mi (63 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 Maple Hill RD Salmon Crk built?

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

What condition is U.S. Highway 101 over Maple Hill RD Salmon Crk 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 U.S. Highway 101 over Maple Hill RD Salmon Crk carry?

About 5,100 vehicles per day (2014 count), of which roughly 16% are trucks.

How long is U.S. Highway 101 over Maple Hill RD Salmon Crk?

The structure is 279 ft (85 m) long with a longest span of 105 ft (32 m) and a deck 62 ft wide.

Who owns U.S. Highway 101 over Maple Hill RD Salmon Crk?

It is owned by the State Highway Agency.