US Bridges

I-5 over S 336th ST

Fair

King County, Washington · 0.8 N JCT SR 18 · Structure no. 0006094C0000000

Built
1959
66 years old, rebuilt 2006
Condition
Fair
inspected May 2023
Type
Slab
Concrete Continuous
Length
156 ft
3 main spans
Daily traffic
92,438
2023 count
Owner
State
State Highway Agency

About this bridge

I-5 over S 336th ST is a concrete continuous slab carrying I-5 over S 336th ST in King County, Washington. It was built in 1959 and reconstructed in 2006, so it is 66 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 92,438 vehicles a day, roughly 7% of them trucks, projected to reach 132,682 by 2039. The structure is 156 ft (47.5 m) long and 83 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-5
CrossesS 336th ST
Location0.8 N JCT SR 18
RouteInterstate 5
CountyKing County
StateWashington
Coordinates47.3004, -122.30321
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55.7 US tons
Inventory rating43.2 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length156 ft (47.5 m)
Longest span61 ft (18.6 m)
Deck width83 ft (25.3 m)
Roadway width80 ft (24.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic92,438 (2023)
Projected traffic132,682 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 statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$6.1 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-5 over S 336th ST built?

It was built in 1959, making it 66 years old in 2025. It was reconstructed in 2006.

What condition is I-5 over S 336th ST 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 May 2023.

How much traffic does I-5 over S 336th ST carry?

About 92,438 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is I-5 over S 336th ST?

The structure is 156 ft (47.5 m) long with a longest span of 61 ft (18.6 m) and a deck 83 ft wide.

Who owns I-5 over S 336th ST?

It is owned by the State Highway Agency.