Structure 85786000000000 · King County, WA

S Jackson ST over ST Tunnel

Carries S Jackson ST over ST Tunnel, S Jackson ST Wo 5th AVE S.

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
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT146 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 7/9

146 ft end to end: 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 multi-beam bridge.

Built198739 years old
Length146.0 ft44.5 m
Daily traffic26,700counted 2018
Last inspectedJuly 2023every 24 months

Location

StateWashington
CountyKing
LocationS Jackson ST Wo 5th AVE S
CarriesS Jackson ST
CrossesST Tunnel
Coordinates47.59917, -122.32833

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length146.0 ft (44.5 m)
Max Span103.0 ft (31.4 m)
Deck Width89.9 ft (27.4 m)
Deck Area1219.3 sq m
Main Spans1
Year Built1987

Traffic

Avg Daily Traffic26,700 (2018)
Truck Traffic10%
Lanes On Bridge5

Inspection & Ownership

Last InspectionJuly 2023
Inspection FrequencyEvery 24 months
OwnerCity/Municipal Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number085786000000000

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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