Structure 4 0016L · Humboldt County, CA

US Highway 101 SB over Eel River

Carries US Highway 101 SB over Eel River, 01-hum-101-m53.97-rdel.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructuresets the rating7/9 · Good
Substructuresets the rating7/9 · Good
Channelnot part of overall9/9 · Excellent
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT1,730 FT OVERALL250 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

1,730 ft end to end, longest span 300 ft: about 4.8 football fields. Lengths and the semi-truck on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a box-beam bridge.

Built197452 years old
Length1730.3 ft527.4 m
Daily traffic4,400counted 2009
Last inspectedJuly 2023every 24 months

Location

StateCalifornia
CountyHumboldt
Location01-hum-101-m53.97-rdel
CarriesUS Highway 101 SB
CrossesEel River
Coordinates40.50824, -124.12004

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignBox Beam - Multiple
Total Length1730.3 ft (527.4 m)
Max Span299.9 ft (91.4 m)
Deck Width41.0 ft (12.5 m)
Deck Area6592.5 sq m
Main Spans7
Year Built1974

Traffic

Avg Daily Traffic4,400 (2009)
Truck Traffic11%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJuly 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure Number04 0016L

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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