US Bridges

I-90 over I-5

Fair

King County, Washington · JCT I-5 · Structure no. 0007565P0000000

Built
1966
59 years old, rebuilt 1991
Condition
Fair
inspected April 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
1,881 ft
10 main spans
Daily traffic
20,960
2023 count
Owner
State
State Highway Agency

About this bridge

I-90 over I-5 is a prestressed concrete continuous box beam or girders - multiple carrying I-90 over I-5 in King County, Washington. It was built in 1966 and reconstructed in 1991, so it is 59 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 20,960 vehicles a day, roughly 3% of them trucks, projected to reach 31,713 by 2039. The structure is 1,881 ft (573.3 m) long and 36 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesI-90
CrossesI-5
LocationJCT I-5
RouteInterstate 90
CountyKing County
StateWashington
Coordinates47.59228, -122.32622
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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating17.2 US tons
Inventory rating13.2 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans10 (+9 approach)
Design loadHS 20 + Mod
Structure length1,881 ft (573.3 m)
Longest span128 ft (39 m)
Deck width36 ft (11 m)
Roadway width33 ft (10.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20,960 (2023)
Projected traffic31,713 by 2039
Trucks3%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed3.1 mi (5 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 statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$39.3 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-90 over I-5 built?

It was built in 1966, making it 59 years old in 2025. It was reconstructed in 1991.

What condition is I-90 over I-5 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 I-90 over I-5 carry?

About 20,960 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is I-90 over I-5?

The structure is 1,881 ft (573.3 m) long with a longest span of 128 ft (39 m) and a deck 36 ft wide.

Who owns I-90 over I-5?

It is owned by the State Highway Agency.