Structure 11598A0000000 · Snohomish County, WA

I-405 over SR 524 (filbert Rd)

Carries I-405 over SR 524 (filbert Rd), 2.9 N Jct SR 527.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructuresets the rating6/9 · Satisfactory
Substructure7/9 · Good
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT341 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 7/9

341 ft end to end, longest span 137 ft: about 5 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.

Built1968rebuilt 2001
Length340.9 ft103.9 m
Daily traffic61,143counted 2023
Last inspectedJune 2024every 24 months

Location

StateWashington
CountySnohomish
Location2.9 N Jct SR 527
CarriesI-405
CrossesSR 524 (filbert Rd)
Coordinates47.82525, -122.25350

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length340.9 ft (103.9 m)
Max Span137.1 ft (41.8 m)
Deck Width81.4 ft (24.8 m)
Deck Area2576.7 sq m
Main Spans3
Year Built1968 (reconstructed 2001)

Traffic

Avg Daily Traffic61,143 (2023)
Truck Traffic5%
Lanes On Bridge4
Lanes Under Bridge2

Inspection & Ownership

Last InspectionJune 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical9 — Foundation above flood level
Structure Number0011598A0000000

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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