US Bridges

SR 18 over BNSF RR Spur

Fair

King County, Washington · 0.8 E JCT SR 164 · Structure no. 0012618A0000000

Built
1986
39 years old
Condition
Fair
inspected November 2023
Type
Box Beam or Girders - Multiple
Concrete
Length
212 ft
3 main spans
Daily traffic
31,748
2023 count
Owner
State
State Highway Agency

About this bridge

SR 18 over BNSF RR Spur is a concrete box beam or girders - multiple carrying SR 18 over BNSF RR Spur in King County, Washington. It was built in 1986, so it is 39 years old, younger 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 31,748 vehicles a day, roughly 11% of them trucks, projected to reach 45,853 by 2039. The structure is 212 ft (64.6 m) long and 41 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesSR 18
CrossesBNSF RR Spur
Location0.8 E JCT SR 164
RouteState Highway 18
CountyKing County
StateWashington
Coordinates47.30347, -122.209
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating82.5 US tons
Inventory rating63.6 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length212 ft (64.6 m)
Longest span83 ft (25.3 m)
Deck width41 ft (12.6 m)
Roadway width40 ft (12.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic31,748 (2023)
Projected traffic45,853 by 2039
Trucks11%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and railroad
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$4.4 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 18 over BNSF RR Spur built?

It was built in 1986, making it 39 years old in 2025.

What condition is SR 18 over BNSF RR Spur 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 November 2023.

How much traffic does SR 18 over BNSF RR Spur carry?

About 31,748 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is SR 18 over BNSF RR Spur?

The structure is 212 ft (64.6 m) long with a longest span of 83 ft (25.3 m) and a deck 41 ft wide.

Who owns SR 18 over BNSF RR Spur?

It is owned by the State Highway Agency.