US Bridges

W.B. I-90 over Lake Washington

Fair

King County, Washington · 3.0 E JCT I-5 · Structure no. 0012833C0000000

Built
1989
36 years old
Condition
Fair
inspected April 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
1,472 ft
1 main span
Daily traffic
68,544
2023 count
Owner
State
State Highway Agency

About this bridge

W.B. I-90 over Lake Washington is a prestressed concrete box beam or girders - multiple carrying W.B. I-90 over Lake Washington in King County, Washington. It was built in 1989, so it is 36 years old, younger 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 68,544 vehicles a day, roughly 3% of them trucks, projected to reach 104,170 by 2039. The structure is 1,472 ft (448.7 m) long and 63 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesW.B. I-90
CrossesLake Washington
Location3.0 E JCT I-5
RouteInterstate 90
CountyKing County
StateWashington
Coordinates47.58975, -122.25875
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44.6 US tons
Inventory rating34.3 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1 (+7 approach)
Design loadHS 20 + Mod
Structure length1,472 ft (448.7 m)
Longest span236 ft (71.9 m)
Deck width63 ft (19.2 m)
Roadway width52 ft (15.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic68,544 (2023)
Projected traffic104,170 by 2039
Trucks3%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway and pedestrian
CrossesHighway and waterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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$37.8 million (2022 estimate)
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was W.B. I-90 over Lake Washington built?

It was built in 1989, making it 36 years old in 2025.

What condition is W.B. I-90 over Lake Washington 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 April 2023.

How much traffic does W.B. I-90 over Lake Washington carry?

About 68,544 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is W.B. I-90 over Lake Washington?

The structure is 1,472 ft (448.7 m) long with a longest span of 236 ft (71.9 m) and a deck 63 ft wide.

Who owns W.B. I-90 over Lake Washington?

It is owned by the State Highway Agency.