US Bridges

I-90 over Big CR

Fair

Kittitas County, Washington · 20.6 E JCT SR 906 · Structure no. 0009428A0000000

Built
1973
52 years old
Condition
Fair
inspected May 2024
Type
Slab
Concrete
Length
55 ft
1 main span
Daily traffic
16,832
2023 count
Owner
State
State Highway Agency

About this bridge

I-90 over Big CR is a concrete slab carrying I-90 over Big CR in Kittitas County, Washington. It was built in 1973, so it is 52 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 16,832 vehicles a day, roughly 23% of them trucks, projected to reach 21,760 by 2039. The structure is 55 ft (16.8 m) long and 41 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-90
CrossesBig CR
Location20.6 E JCT SR 906
RouteInterstate 90
CountyKittitas County
StateWashington
Coordinates47.21212, -121.10386
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMay 2024
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 geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating67 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length55 ft (16.8 m)
Longest span50 ft (15.2 m)
Deck width41 ft (12.5 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,832 (2023)
Projected traffic21,760 by 2039
Trucks23%
Lanes on structure2
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 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-90 over Big CR built?

It was built in 1973, making it 52 years old in 2025.

What condition is I-90 over Big CR 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 May 2024.

How much traffic does I-90 over Big CR carry?

About 16,832 vehicles per day (2023 count), of which roughly 23% are trucks.

How long is I-90 over Big CR?

The structure is 55 ft (16.8 m) long with a longest span of 50 ft (15.2 m) and a deck 41 ft wide.

Who owns I-90 over Big CR?

It is owned by the State Highway Agency.