US Bridges

8th Ave over I-5

Fair

King County, Washington · 1.3 N JCT I-90 · Structure no. 0007409A0000000

Built
1964
61 years old, rebuilt 1987
Condition
Fair
inspected April 2023
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
859 ft
9 main spans
Daily traffic
4,900
2014 count
Owner
State
State Highway Agency

About this bridge

8th Ave over I-5 is a concrete continuous box beam or girders - multiple carrying 8th Ave over I-5 in King County, Washington. It was built in 1964 and reconstructed in 1987, so it is 61 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 4,900 vehicles a day, roughly 5% of them trucks, projected to reach 7,056 by 2034. The structure is 859 ft (261.8 m) long and 39 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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Carries8th Ave
CrossesI-5
Location1.3 N JCT I-90
RouteCity Street 0
CountyKing County
StateWashington
Coordinates47.61063, -122.33089
Functional classUrban Minor 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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating70 US tons
Inventory rating41 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans9 (+2 approach)
Design loadHS 20
Structure length859 ft (261.8 m)
Longest span144 ft (43.9 m)
Deck width39 ft (11.9 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,900 (2014)
Projected traffic7,056 by 2034
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

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$25.3 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was 8th Ave over I-5 built?

It was built in 1964, making it 61 years old in 2025. It was reconstructed in 1987.

What condition is 8th Ave 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 8th Ave over I-5 carry?

About 4,900 vehicles per day (2014 count), of which roughly 5% are trucks.

How long is 8th Ave over I-5?

The structure is 859 ft (261.8 m) long with a longest span of 144 ft (43.9 m) and a deck 39 ft wide.

Who owns 8th Ave over I-5?

It is owned by the State Highway Agency.