Structure 11598C0000000 · Snohomish County, WA

I-5 over S 405 & N 525 Ramps

Carries I-5 over S 405 & N 525 Ramps, 1.1 N Jct SR 524.

Overall conditionFair

Set by its lowest-rated component: Deck at 6 of 9.

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure7/9 · Good
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT275 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 7/9

275 ft end to end, longest span 138 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 multi-beam bridge.

Built1980rebuilt 1995
Length274.9 ft83.8 m
Daily traffic69,203counted 2023
Last inspectedFebruary 2024every 24 months

Location

StateWashington
CountySnohomish
Location1.1 N Jct SR 524
CarriesI-5
CrossesS 405 & N 525 Ramps
Coordinates47.83203, -122.26278

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignStringer/Multi-beam
Total Length274.9 ft (83.8 m)
Max Span138.1 ft (42.1 m)
Deck Width70.9 ft (21.6 m)
Deck Area1810.1 sq m
Main Spans2
Year Built1980 (reconstructed 1995)

Traffic

Avg Daily Traffic69,203 (2023)
Truck Traffic6%
Lanes On Bridge4
Lanes Under Bridge4

Inspection & Ownership

Last InspectionFebruary 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number0011598C0000000

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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