US Bridges

SR 99 over Spokane ST

FairPosted for load

King County, Washington · 2.1 N JCT SR 509 · Structure no. 0005758A0000000

Built
1959
66 years old, rebuilt 2013
Condition
Fair
inspected October 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
2,792 ft
3 main spans
Daily traffic
18,505
2023 count
Owner
State
State Highway Agency

About this bridge

SR 99 over Spokane ST is a steel stringer/multi-beam or girder carrying SR 99 over Spokane ST in King County, Washington. It was built in 1959 and reconstructed in 2013, so it is 66 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 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 18,505 vehicles a day, roughly 4% of them trucks, projected to reach 30,439 by 2039. The structure is 2,792 ft (851 m) long and 84 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesSR 99
CrossesSpokane ST
Location2.1 N JCT SR 509
RouteState Highway 99
CountyKing County
StateWashington
Coordinates47.56753, -122.33942
Functional classUrban Principal Arterial - Other Freeway or Expressway

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourBridge not over waterway
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating36 US tons
Inventory rating20.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3 (+41 approach)
Design loadHS 20
Structure length2,792 ft (851 m)
Longest span135 ft (41.1 m)
Deck width84 ft (25.6 m)
Roadway width76 ft (23.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,505 (2023)
Projected traffic30,439 by 2039
Trucks4%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and railroad
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$106.1 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 99 over Spokane ST built?

It was built in 1959, making it 66 years old in 2025. It was reconstructed in 2013.

What condition is SR 99 over Spokane ST 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 October 2023.

How much traffic does SR 99 over Spokane ST carry?

About 18,505 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is SR 99 over Spokane ST?

The structure is 2,792 ft (851 m) long with a longest span of 135 ft (41.1 m) and a deck 84 ft wide.

Who owns SR 99 over Spokane ST?

It is owned by the State Highway Agency.