US Bridges

I-90 over Coal Creek

Fair

Kittitas County, Washington · 2.0 E King CO · Structure no. 0004074A0000000

Built
1950
75 years old, rebuilt 1968
Condition
Fair
inspected September 2023
Type
Culvert
Concrete
Length
21 ft
2 main spans
Daily traffic
17,758
2023 count
Owner
State
State Highway Agency

About this bridge

I-90 over Coal Creek is a concrete culvert carrying I-90 over Coal Creek in Kittitas County, Washington. It was built in 1950 and reconstructed in 1968, so it is 75 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 17,758 vehicles a day, roughly 21% of them trucks, projected to reach 21,804 by 2039. The structure is 21 ft (6.4 m) long. If it were closed, the detour would be 9.9 mi (16 km).

Location

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CarriesI-90
CrossesCoal Creek
Location2.0 E King CO
RouteInterstate 90
CountyKittitas County
StateWashington
Coordinates47.39824, -121.39885
Functional classRural Principal Arterial - Interstate

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: 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 rating99 US tons
Inventory rating99 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadHS 20
Structure length21 ft (6.4 m)
Longest span10 ft (3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic17,758 (2023)
Projected traffic21,804 by 2039
Trucks21%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$658,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-90 over Coal Creek built?

It was built in 1950, making it 75 years old in 2025. It was reconstructed in 1968.

What condition is I-90 over Coal Creek 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 September 2023.

How much traffic does I-90 over Coal Creek carry?

About 17,758 vehicles per day (2023 count), of which roughly 21% are trucks.

How long is I-90 over Coal Creek?

The structure is 21 ft (6.4 m) long with a longest span of 10 ft (3 m).

Who owns I-90 over Coal Creek?

It is owned by the State Highway Agency.