US Bridges

I-90 over Avalanche Relief

Good

Kittitas County, Washington · 3.3 E JCT SR 906 · Structure no. 0018127A0000000

Built
2016
9 years old
Condition
Good
inspected July 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
1,206 ft
8 main spans
Daily traffic
18,069
2023 count
Owner
State
State Highway Agency

About this bridge

I-90 over Avalanche Relief is a prestressed concrete continuous stringer/multi-beam or girder carrying I-90 over Avalanche Relief in Kittitas County, Washington. It was built in 2016, so it is 9 years old, younger than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 18,069 vehicles a day, roughly 21% of them trucks, projected to reach 22,265 by 2039. The structure is 1,206 ft (367.6 m) long and 59 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-90
CrossesAvalanche Relief
Location3.3 E JCT SR 906
RouteInterstate 90
CountyKittitas County
StateWashington
Coordinates47.35708, -121.36742
Functional classRural Principal Arterial - Interstate

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations on dry land well above flood water elevations
Structural evaluation8: Equal to present desirable criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48.2 US tons
Inventory rating37.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans8
Design loadHL 93
Structure length1,206 ft (367.6 m)
Longest span170 ft (51.8 m)
Deck width59 ft (18 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,069 (2023)
Projected traffic22,265 by 2039
Trucks21%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesOther
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

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$33.2 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-90 over Avalanche Relief built?

It was built in 2016, making it 9 years old in 2025.

What condition is I-90 over Avalanche Relief in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in July 2024.

How much traffic does I-90 over Avalanche Relief carry?

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

How long is I-90 over Avalanche Relief?

The structure is 1,206 ft (367.6 m) long with a longest span of 170 ft (51.8 m) and a deck 59 ft wide.

Who owns I-90 over Avalanche Relief?

It is owned by the State Highway Agency.