Structure 7046A0000000 · King County, WA

SR 99 over SR 518 Riverton Hts

Carries SR 99 over SR 518 Riverton Hts, 4.9 N Jct SR 516.

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
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT324 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 7/9

324 ft end to end, longest span 97 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 multi-beam bridge.

Built1962rebuilt 2011
Length324.1 ft98.8 m
Daily traffic33,632counted 2023
Last inspectedMarch 2024every 24 months

Location

StateWashington
CountyKing
Location4.9 N Jct SR 516
CarriesSR 99
CrossesSR 518 Riverton Hts
Coordinates47.46303, -122.29011

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length324.1 ft (98.8 m)
Max Span97.1 ft (29.6 m)
Deck Width90.6 ft (27.6 m)
Deck Area2726.9 sq m
Main Spans4
Year Built1962 (reconstructed 2011)

Traffic

Avg Daily Traffic33,632 (2023)
Truck Traffic9%
Lanes On Bridge6
Lanes Under Bridge10

Inspection & Ownership

Last InspectionMarch 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number0007046A0000000

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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