US Bridges

Cumberland-Kanaske over Green River

Fair

King County, Washington · 4.25 MI E of SR-169 · Structure no. 081163000000000

Built
1918
107 years old, rebuilt 1955
Condition
Fair
inspected August 2024
Type
Arch - Deck
Concrete Continuous
Length
220 ft
1 main span
Daily traffic
2,061
2019 count
Owner
County
County Highway Agency

About this bridge

Cumberland-Kanaske over Green River is a concrete continuous arch - deck carrying Cumberland-Kanaske over Green River in King County, Washington. It was built in 1918 and reconstructed in 1955, so it is 107 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 2,061 vehicles a day, roughly 18% of them trucks, projected to reach 3,720 by 2041. The structure is 220 ft (67.1 m) long and 26 ft wide. If it were closed, the detour would be 16.2 mi (26 km).

Location

Open in Google Maps
CarriesCumberland-Kanaske
CrossesGreen River
Location4.25 MI E of SR-169
RouteCounty Highway 93655
CountyKing County
StateWashington
Coordinates47.31917, -121.89353
Functional classRural Major Collector

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating48.9 US tons
Inventory rating40 US tons

Structure

Structure typeArch - Deck
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans1 (+2 approach)
Design loadHS 20
Structure length220 ft (67.1 m)
Longest span100 ft (30.5 m)
Deck width26 ft (7.8 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,061 (2019)
Projected traffic3,720 by 2041
Trucks18%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed16.2 mi (26 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$8.3 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Cumberland-Kanaske over Green River built?

It was built in 1918, making it 107 years old in 2025. It was reconstructed in 1955.

What condition is Cumberland-Kanaske over Green River 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 2024.

How much traffic does Cumberland-Kanaske over Green River carry?

About 2,061 vehicles per day (2019 count), of which roughly 18% are trucks.

How long is Cumberland-Kanaske over Green River?

The structure is 220 ft (67.1 m) long with a longest span of 100 ft (30.5 m) and a deck 26 ft wide.

Who owns Cumberland-Kanaske over Green River?

It is owned by the County Highway Agency.