US Bridges

150th Ave SE over I-90

Fair

King County, Washington · 1.7 E JCT I-405 · Structure no. 0009134A0000000

Built
1973
52 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
404 ft
2 main spans
Daily traffic
18,919
2007 count
Owner
State
State Highway Agency

About this bridge

150th Ave SE over I-90 is a steel continuous stringer/multi-beam or girder carrying 150th Ave SE over I-90 in King County, Washington. It was built in 1973, so it is 52 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.

It carries about 18,919 vehicles a day, roughly 5% of them trucks, projected to reach 32,635 by 2036. The structure is 404 ft (123.1 m) long and 63 ft wide.

Location

Open in Google Maps
Carries150th Ave SE
CrossesI-90
Location1.7 E JCT I-405
RouteCity Street 90
CountyKing County
StateWashington
Coordinates47.57839, -122.14031
Functional classUrban Other Principal 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionAugust 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 geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating31.4 US tons
Inventory rating24.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20 + Mod
Structure length404 ft (123.1 m)
Longest span199 ft (60.7 m)
Deck width63 ft (19.3 m)
Roadway width50 ft (15.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,919 (2007)
Projected traffic32,635 by 2036
Trucks5%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed—
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$11.9 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was 150th Ave SE over I-90 built?

It was built in 1973, making it 52 years old in 2025.

What condition is 150th Ave SE over I-90 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 August 2023.

How much traffic does 150th Ave SE over I-90 carry?

About 18,919 vehicles per day (2007 count), of which roughly 5% are trucks.

How long is 150th Ave SE over I-90?

The structure is 404 ft (123.1 m) long with a longest span of 199 ft (60.7 m) and a deck 63 ft wide.

Who owns 150th Ave SE over I-90?

It is owned by the State Highway Agency.