Structure 85179000000000 · King County, WA

15th AVE W over Ship Canal

Carries 15th AVE W over Ship Canal, 4300 15th AVE W.

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 overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT295 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 5/9 · sets the ratingSubstructure 5/9 · sets the rating

295 ft end to end, longest span 218 ft: about 4 semi-trucks nose to tail. 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 bascule bridge (drawn closed).

Built1917109 years old
Length294.9 ft89.9 m
Daily traffic60,000counted 2020
Last inspectedApril 2024every 24 months

Location

StateWashington
CountyKing
Location4300 15th AVE W
Carries15th AVE W
CrossesShip Canal
Coordinates47.65983, -122.37612

Physical Characteristics

MaterialSteel
DesignMovable - Bascule
Total Length294.9 ft (89.9 m)
Max Span217.8 ft (66.4 m)
Deck Width52.5 ft (16 m)
Deck Area1438.4 sq m
Main Spans3
Year Built1917

Traffic

Avg Daily Traffic60,000 (2020)
Truck Traffic10%
Lanes On Bridge4

Inspection & Ownership

Last InspectionApril 2024
Inspection FrequencyEvery 24 months
OwnerCity/Municipal Highway Agency
Historical SignificanceBridge is on the National Register of Historic Places
Scour Critical8 — Stable, low risk
Structure Number085179000000000

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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