Structure 16611B0000000 · King County, WA

SR 18 over Cedar River SE Bain RD

Carries SR 18 over Cedar River SE Bain RD, 5.2 N Jct SR 516.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure7/9 · Good
Substructure7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT351 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 7/9

351 ft end to end, longest span 125 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.

Built200422 years old
Length351.0 ft107 m
Daily traffic16,971counted 2023
Last inspectedFebruary 2023every 24 months

Location

StateWashington
CountyKing
Location5.2 N Jct SR 516
CarriesSR 18
CrossesCedar River SE Bain RD
Coordinates47.40619, -122.04206

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignStringer/Multi-beam
Total Length351.0 ft (107 m)
Max Span125.0 ft (38.1 m)
Deck Width48.6 ft (14.8 m)
Deck Area1583.6 sq m
Main Spans3
Year Built2004

Traffic

Avg Daily Traffic16,971 (2023)
Truck Traffic14%
Lanes On Bridge2
Lanes Under Bridge2

Inspection & Ownership

Last InspectionFebruary 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceHistorical significance is not determined
Scour Critical5 — Stable for scour
Structure Number0016611B0000000

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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