US Bridges

SR 520 W-S Ramp over I-5

Fair

King County, Washington · 0.1 E JCT I-5 · Structure no. 0006470C0000000

Built
1962
63 years old
Condition
Fair
inspected August 2023
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
351 ft
3 main spans
Daily traffic
18,129
2023 count
Owner
State
State Highway Agency

About this bridge

SR 520 W-S Ramp over I-5 is a concrete continuous box beam or girders - multiple carrying SR 520 W-S Ramp over I-5 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 18,129 vehicles a day, roughly 3% of them trucks, projected to reach 36,481 by 2039. The structure is 351 ft (107 m) long and 32 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesSR 520 W-S Ramp
CrossesI-5
Location0.1 E JCT I-5
RouteState Highway 520
CountyKing County
StateWashington
Coordinates47.64222, -122.32239
Functional classUrban Principal Arterial - Other Freeway or Expressway

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 inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment8: Equal to present desirable criteria
Operating rating89.9 US tons
Inventory rating53 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length351 ft (107 m)
Longest span141 ft (42.9 m)
Deck width32 ft (9.9 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,129 (2023)
Projected traffic36,481 by 2039
Trucks3%
Lanes on structure2
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 statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$5.3 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 520 W-S Ramp over I-5 built?

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

What condition is SR 520 W-S Ramp 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 August 2023.

How much traffic does SR 520 W-S Ramp over I-5 carry?

About 18,129 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is SR 520 W-S Ramp over I-5?

The structure is 351 ft (107 m) long with a longest span of 141 ft (42.9 m) and a deck 32 ft wide.

Who owns SR 520 W-S Ramp over I-5?

It is owned by the State Highway Agency.