US Bridges

10th Ave over SR 520

Fair

King County, Washington · 0.1 E JCT I-5 · Structure no. 0006861B0000000

Built
1962
63 years old
Condition
Fair
inspected August 2023
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
285 ft
3 main spans
Daily traffic
13,800
2012 count
Owner
State
State Highway Agency

About this bridge

10th Ave over SR 520 is a concrete continuous box beam or girders - multiple carrying 10th Ave over SR 520 in King County, Washington. It was built in 1962, so it is 63 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 13,800 vehicles a day, roughly 3% of them trucks, projected to reach 21,086 by 2036. The structure is 285 ft (86.9 m) long and 62 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
Carries10th Ave
CrossesSR 520
Location0.1 E JCT I-5
RouteCity Street 0
CountyKing County
StateWashington
Coordinates47.64209, -122.32005
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating36 US tons
Inventory rating27.9 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length285 ft (86.9 m)
Longest span117 ft (35.7 m)
Deck width62 ft (18.8 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,800 (2012)
Projected traffic21,086 by 2036
Trucks3%
Lanes on structure3
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed1.2 mi (2 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$6.2 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was 10th Ave over SR 520 built?

It was built in 1962, making it 63 years old in 2025.

What condition is 10th Ave over SR 520 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 August 2023.

How much traffic does 10th Ave over SR 520 carry?

About 13,800 vehicles per day (2012 count), of which roughly 3% are trucks.

How long is 10th Ave over SR 520?

The structure is 285 ft (86.9 m) long with a longest span of 117 ft (35.7 m) and a deck 62 ft wide.

Who owns 10th Ave over SR 520?

It is owned by the State Highway Agency.