Structure 13221B0000000 · King County, WA

North Mercer Way over I-90

Carries North Mercer Way over I-90, 5.0 E Jct SR 900.

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 FT255 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

255 ft end to end, longest span 85 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 box-beam bridge.

Built198937 years old
Length254.9 ft77.7 m
Daily traffic2,922counted 2002
Last inspectedJune 2024every 24 months

Location

StateWashington
CountyKing
Location5.0 E Jct SR 900
CarriesNorth Mercer Way
CrossesI-90
Coordinates47.57856, -122.21289

Physical Characteristics

MaterialConcrete Continuous
DesignBox Beam - Multiple
Total Length254.9 ft (77.7 m)
Max Span85.0 ft (25.9 m)
Deck Width148.0 ft (45.1 m)
Deck Area3504.3 sq m
Main Spans3
Year Built1989

Traffic

Avg Daily Traffic2,922 (2002)
Truck Traffic2%
Lanes On Bridge2
Lanes Under Bridge10

Inspection & Ownership

Last InspectionJune 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is eligible for the National Register
Scour CriticalNot applicable
Structure Number0013221B0000000

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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