US Bridges

NE 18th ST over Drainage Ditch

Fair

King County, Washington · 1.6 MI W of SR-203 · Structure no. 083935000000000

Built
1965
60 years old
Condition
Fair
inspected July 2024
Type
Tee Beam
Concrete
Length
36 ft
1 main span
Daily traffic
798
2020 count
Owner
County
County Highway Agency

About this bridge

NE 18th ST over Drainage Ditch is a concrete tee beam carrying NE 18th ST over Drainage Ditch in King County, Washington. It was built in 1965, so it is 60 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 798 vehicles a day, roughly 6% of them trucks, projected to reach 1,440 by 2040. The structure is 36 ft (11 m) long and 28 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesNE 18th ST
CrossesDrainage Ditch
Location1.6 MI W of SR-203
RouteCounty Highway 67850
CountyKing County
StateWashington
Coordinates47.62223, -121.93477
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2024
Inspection intervalevery 12 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckOther
Main spans1
Design loadHS 20
Structure length36 ft (11 m)
Longest span36 ft (11 m)
Deck width28 ft (8.5 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic798 (2020)
Projected traffic1,440 by 2040
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.7 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was NE 18th ST over Drainage Ditch built?

It was built in 1965, making it 60 years old in 2025.

What condition is NE 18th ST over Drainage Ditch 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 July 2024.

How much traffic does NE 18th ST over Drainage Ditch carry?

About 798 vehicles per day (2020 count), of which roughly 6% are trucks.

How long is NE 18th ST over Drainage Ditch?

The structure is 36 ft (11 m) long with a longest span of 36 ft (11 m) and a deck 28 ft wide.

Who owns NE 18th ST over Drainage Ditch?

It is owned by the County Highway Agency.