US Bridges

S Jackson ST over Parking Garage

Fair

King County, Washington · S Jackson ST Eo 4th Ave S · Structure no. 085048000000000

Built
1910
115 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Concrete Continuous
Length
143 ft
7 main spans
Daily traffic
15,000
2020 count
Owner
City
City or Municipal Highway Agency

About this bridge

S Jackson ST over Parking Garage is a concrete continuous stringer/multi-beam or girder carrying S Jackson ST over Parking Garage in King County, Washington. It was built in 1910, so it is 115 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 15,000 vehicles a day, roughly 5% of them trucks, projected to reach 20,000 by 2043. The structure is 143 ft (43.6 m) long and 90 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesS Jackson ST
CrossesParking Garage
LocationS Jackson ST Eo 4th Ave S
RouteCity Street 1140
CountyKing County
StateWashington
Coordinates47.5992, -122.32861
Functional classUrban Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55 US tons
Inventory rating32 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans7
Design loadHS 25 or greater
Structure length143 ft (43.6 m)
Longest span41 ft (12.5 m)
Deck width90 ft (27.4 m)
Roadway width55 ft (16.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15,000 (2020)
Projected traffic20,000 by 2043
Trucks5%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesOther
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$3.9 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was S Jackson ST over Parking Garage built?

It was built in 1910, making it 115 years old in 2025.

What condition is S Jackson ST over Parking Garage in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in July 2023.

How much traffic does S Jackson ST over Parking Garage carry?

About 15,000 vehicles per day (2020 count), of which roughly 5% are trucks.

How long is S Jackson ST over Parking Garage?

The structure is 143 ft (43.6 m) long with a longest span of 41 ft (12.5 m) and a deck 90 ft wide.

Who owns S Jackson ST over Parking Garage?

It is owned by the City or Municipal Highway Agency.