Structure 6066B0000000 · King County, WA

SR 18 over Green River

Carries SR 18 over Green River, 2.5 E Jct SR 164.

Overall conditionFair

Set by its lowest-rated component: Superstructure at 5 of 9.

How ratings work
Deck6/9 · Satisfactory
Superstructuresets the rating5/9 · Fair
Substructure6/9 · Satisfactory
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT371 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 5/9 · sets the ratingSubstructure 6/9

371 ft end to end: 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 through truss.

Built195967 years old
Length371.1 ft113.1 m
Daily traffic28,147counted 2023
Last inspectedApril 2024every 24 months

Location

StateWashington
CountyKing
Location2.5 E Jct SR 164
CarriesSR 18
CrossesGreen River
Coordinates47.30246, -122.17746

Physical Characteristics

MaterialSteel
DesignTruss - Thru
Total Length371.1 ft (113.1 m)
Max Span200.1 ft (61 m)
Deck Width32.8 ft (10 m)
Deck Area1,131 sq m
Main Spans1
Year Built1959

Traffic

Avg Daily Traffic28,147 (2023)
Truck Traffic11%
Lanes On Bridge2

Inspection & Ownership

Last InspectionApril 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceHistorical significance is not determined
Scour Critical3 — Scour critical
Structure Number0006066B0000000

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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