US Bridges

I-5 over Interurban Ave

Fair

King County, Washington · 0.1 N JCT SR 599 · Structure no. 0007618C0000000

Built
1966
59 years old, rebuilt 1996
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
160 ft
3 main spans
Daily traffic
86,409
2023 count
Owner
State
State Highway Agency

About this bridge

I-5 over Interurban Ave is a prestressed concrete stringer/multi-beam or girder carrying I-5 over Interurban Ave in King County, Washington. It was built in 1966 and reconstructed in 1996, 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 86,409 vehicles a day, roughly 7% of them trucks, projected to reach 129,041 by 2039. The structure is 160 ft (48.8 m) long and 79 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-5
CrossesInterurban Ave
Location0.1 N JCT SR 599
RouteInterstate 5
CountyKing County
StateWashington
Coordinates47.48333, -122.27053
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.
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating32.8 US tons
Inventory rating25.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length160 ft (48.8 m)
Longest span66 ft (20.1 m)
Deck width79 ft (24.1 m)
Roadway width76 ft (23.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic86,409 (2023)
Projected traffic129,041 by 2039
Trucks7%
Lanes on structure5
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 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$5.9 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-5 over Interurban Ave built?

It was built in 1966, making it 59 years old in 2025. It was reconstructed in 1996.

What condition is I-5 over Interurban Ave 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 I-5 over Interurban Ave carry?

About 86,409 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is I-5 over Interurban Ave?

The structure is 160 ft (48.8 m) long with a longest span of 66 ft (20.1 m) and a deck 79 ft wide.

Who owns I-5 over Interurban Ave?

It is owned by the State Highway Agency.