Structure 7742A0000000 · King County, WA

I-405 over 115th AVE NE & Trail

Carries I-405 over 115th AVE NE & Trail, 0.2 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 FT296 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

296 ft end to end, longest span 91 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.

Built1965rebuilt 1993
Length295.9 ft90.2 m
Daily traffic67,108counted 2023
Last inspectedAugust 2024every 24 months

Location

StateWashington
CountyKing
Location0.2 N Jct SR 520
CarriesI-405
Crosses115th AVE NE & Trail
Coordinates47.63442, -122.18700

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignStringer/Multi-beam
Total Length295.9 ft (90.2 m)
Max Span90.9 ft (27.7 m)
Deck Width83.0 ft (25.3 m)
Deck Area2282.1 sq m
Main Spans4
Year Built1965 (reconstructed 1993)

Traffic

Avg Daily Traffic67,108 (2023)
Truck Traffic6%
Lanes On Bridge5
Lanes Under Bridge2

Inspection & Ownership

Last InspectionAugust 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number0007742A0000000

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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