Structure 88542000000000 · King County, WA

Airport Nb-sb Loop over Airport Expressway

Carries Airport Nb-sb Loop over Airport Expressway, 0.25 Mi S Of Sr518.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 8 of 9.

How ratings work
Decksets the rating8/9 · Very Good
Superstructuresets the rating8/9 · Very Good
Substructuresets the rating8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT164 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 8/9Substructure 8/9

164 ft end to end, longest span 131 ft: about 2 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.

Built201016 years old
Length164.0 ft50 m
Daily traffic40,000counted 2016
Last inspectedMay 2023every 24 months

Location

StateWashington
CountyKing
Location0.25 Mi S Of Sr518
CarriesAirport Nb-sb Loop
CrossesAirport Expressway
Coordinates47.45947, -122.29823

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length164.0 ft (50 m)
Max Span130.9 ft (39.9 m)
Deck Width44.9 ft (13.7 m)
Deck Area685 sq m
Main Spans2
Year Built2010

Traffic

Avg Daily Traffic40,000 (2016)
Truck Traffic2%
Lanes On Bridge2
Lanes Under Bridge6

Inspection & Ownership

Last InspectionMay 2023
Inspection FrequencyEvery 24 months
OwnerOther Local Agencies
Historical SignificanceHistorical significance is not determined
Scour CriticalNot applicable
Structure Number088542000000000

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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