Structure 6304B0000000 · King County, WA

I-5 S Ramp To 45th over 50th Ramp To I-5 S

Carries I-5 S Ramp To 45th over 50th Ramp To I-5 S, 1.4 N Jct SR 520.

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
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT243 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

243 ft end to end, longest span 70 ft: about 3 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 box-beam bridge.

Built196165 years old
Length243.1 ft74.1 m
Daily traffic10,013counted 2022
Last inspectedMay 2023every 48 months

Location

StateWashington
CountyKing
Location1.4 N Jct SR 520
CarriesI-5 S Ramp To 45th
Crosses50th Ramp To I-5 S
Coordinates47.66300, -122.32250

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length243.1 ft (74.1 m)
Max Span69.9 ft (21.3 m)
Deck Width27.2 ft (8.3 m)
Deck Area615.0 sq m
Main Spans4
Year Built1961

Traffic

Avg Daily Traffic10,013 (2022)
Truck Traffic5%
Lanes On Bridge1
Lanes Under Bridge1

Inspection & Ownership

Last InspectionMay 2023
Inspection FrequencyEvery 48 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number0006304B0000000

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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