US Bridges

SR 520 over 108th Ave NE

Good

King County, Washington · 5.2 E JCT SR 513 · Structure no. 0017963B0000000

Built
2013
12 years old
Condition
Good
inspected January 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
235 ft
2 main spans
Daily traffic
26,760
2023 count
Owner
State
State Highway Agency

About this bridge

SR 520 over 108th Ave NE is a prestressed concrete continuous stringer/multi-beam or girder carrying SR 520 over 108th Ave NE in King County, Washington. It was built in 2013, so it is 12 years old, younger than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 26,760 vehicles a day, roughly 3% of them trucks, projected to reach 48,372 by 2039. The structure is 235 ft (71.6 m) long and 58 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesSR 520
Crosses108th Ave NE
Location5.2 E JCT SR 513
RouteState Highway 520
CountyKing County
StateWashington
Coordinates47.64049, -122.19678
Functional classUrban Principal Arterial - Other Freeway or Expressway

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48.9 US tons
Inventory rating37.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHL 93
Structure length235 ft (71.6 m)
Longest span149 ft (45.4 m)
Deck width58 ft (17.7 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic26,760 (2023)
Projected traffic48,372 by 2039
Trucks3%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

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$6.5 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 520 over 108th Ave NE built?

It was built in 2013, making it 12 years old in 2025.

What condition is SR 520 over 108th Ave NE in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in January 2024.

How much traffic does SR 520 over 108th Ave NE carry?

About 26,760 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is SR 520 over 108th Ave NE?

The structure is 235 ft (71.6 m) long with a longest span of 149 ft (45.4 m) and a deck 58 ft wide.

Who owns SR 520 over 108th Ave NE?

It is owned by the State Highway Agency.