Structure 1764A0000000 · Jefferson County, WA

US 101 over Duckabush Slough

Carries US 101 over Duckabush Slough, 25.0 S Jct SR 104.

Overall conditionFair

Set by its lowest-rated component: Superstructure and Substructure at 5 of 9.

How ratings work
Deck6/9 · Satisfactory
Superstructuresets the rating5/9 · Fair
Substructuresets the rating5/9 · Fair
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT121 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 5/9 · sets the ratingSubstructure 5/9 · sets the rating

121 ft end to end, longest span 30 ft. 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 tee-beam bridge.

Built193492 years old
Length121.1 ft36.9 m
Daily traffic2,967counted 2023
Last inspectedOctober 2024every 24 months

Location

StateWashington
CountyJefferson
Location25.0 S Jct SR 104
CarriesUS 101
CrossesDuckabush Slough
Coordinates47.65117, -122.93300

Physical Characteristics

MaterialConcrete
DesignTee Beam
Total Length121.1 ft (36.9 m)
Max Span29.9 ft (9.1 m)
Deck Width30.5 ft (9.3 m)
Deck Area343.2 sq m
Main Spans4
Year Built1934

Traffic

Avg Daily Traffic2,967 (2023)
Truck Traffic11%
Lanes On Bridge2

Inspection & Ownership

Last InspectionOctober 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure Number0001764A0000000

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.

Nearby Bridges