US Bridges

Cloverdale ST over SR 509

Fair

King County, Washington · 4.0 N JCT SR 518 · Structure no. 0008276G0000000

Built
1968
57 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
333 ft
1 main span
Daily traffic
14,039
2012 count
Owner
State
State Highway Agency

About this bridge

Cloverdale ST over SR 509 is a steel stringer/multi-beam or girder carrying Cloverdale ST over SR 509 in King County, Washington. It was built in 1968, so it is 57 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 5 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 14,039 vehicles a day, roughly 4% of them trucks, projected to reach 22,462 by 2036. The structure is 333 ft (101.5 m) long and 80 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesCloverdale ST
CrossesSR 509
Location4.0 N JCT SR 518
RouteCity Street 0
CountyKing County
StateWashington
Coordinates47.52647, -122.33411
Functional classUrban Other Principal 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating61.9 US tons
Inventory rating37 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+3 approach)
Design loadHS 20
Structure length333 ft (101.5 m)
Longest span85 ft (25.9 m)
Deck width80 ft (24.4 m)
Roadway width68 ft (20.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic14,039 (2012)
Projected traffic22,462 by 2036
Trucks4%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
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$11.1 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was Cloverdale ST over SR 509 built?

It was built in 1968, making it 57 years old in 2025.

What condition is Cloverdale ST over SR 509 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 Cloverdale ST over SR 509 carry?

About 14,039 vehicles per day (2012 count), of which roughly 4% are trucks.

How long is Cloverdale ST over SR 509?

The structure is 333 ft (101.5 m) long with a longest span of 85 ft (25.9 m) and a deck 80 ft wide.

Who owns Cloverdale ST over SR 509?

It is owned by the State Highway Agency.