US Bridges

I-90 over Coal Creek

Fair

Kittitas County, Washington · 0.5 E JCT SR 906 · Structure no. 0001140A0000000

Built
1928
97 years old, rebuilt 1972
Condition
Fair
inspected July 2023
Type
Tee Beam
Concrete
Length
52 ft
1 main span
Daily traffic
18,069
2023 count
Owner
State
State Highway Agency

About this bridge

I-90 over Coal Creek is a concrete tee beam carrying I-90 over Coal Creek in Kittitas County, Washington. It was built in 1928 and reconstructed in 1972, so it is 97 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 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 18,069 vehicles a day, roughly 21% of them trucks, projected to reach 22,265 by 2039. The structure is 52 ft (15.8 m) long and 54 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-90
CrossesCoal Creek
Location0.5 E JCT SR 906
RouteInterstate 90
CountyKittitas County
StateWashington
Coordinates47.39294, -121.38944
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
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 rating47.8 US tons
Inventory rating36.8 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length52 ft (15.8 m)
Longest span50 ft (15.2 m)
Deck width54 ft (16.6 m)
Roadway width52 ft (15.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,069 (2023)
Projected traffic22,265 by 2039
Trucks21%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$1.3 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-90 over Coal Creek built?

It was built in 1928, making it 97 years old in 2025. It was reconstructed in 1972.

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 July 2023.

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

About 18,069 vehicles per day (2023 count), of which roughly 21% are trucks.

How long is I-90 over Coal Creek?

The structure is 52 ft (15.8 m) long with a longest span of 50 ft (15.2 m) and a deck 54 ft wide.

Who owns I-90 over Coal Creek?

It is owned by the State Highway Agency.