US Bridges

I-90 over W Snoqualmie Ic

Good

King County, Washington · 1.7 E JCT SR 18 · Structure no. 0009900C0000000

Built
1976
49 years old
Condition
Good
inspected June 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
135 ft
1 main span
Daily traffic
26,372
2023 count
Owner
State
State Highway Agency

About this bridge

I-90 over W Snoqualmie Ic is a prestressed concrete box beam or girders - multiple carrying I-90 over W Snoqualmie Ic in King County, Washington. It was built in 1976, so it is 49 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 26,372 vehicles a day, roughly 18% of them trucks, projected to reach 34,814 by 2039. The structure is 135 ft (41.1 m) long and 55 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-90
CrossesW Snoqualmie Ic
Location1.7 E JCT SR 18
RouteInterstate 90
CountyKing County
StateWashington
Coordinates47.51283, -121.84944
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating77.5 US tons
Inventory rating48.6 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length135 ft (41.1 m)
Longest span129 ft (39.3 m)
Deck width55 ft (16.8 m)
Roadway width52 ft (15.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic26,372 (2023)
Projected traffic34,814 by 2039
Trucks18%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
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$3.5 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-90 over W Snoqualmie Ic built?

It was built in 1976, making it 49 years old in 2025.

What condition is I-90 over W Snoqualmie Ic 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 June 2023.

How much traffic does I-90 over W Snoqualmie Ic carry?

About 26,372 vehicles per day (2023 count), of which roughly 18% are trucks.

How long is I-90 over W Snoqualmie Ic?

The structure is 135 ft (41.1 m) long with a longest span of 129 ft (39.3 m) and a deck 55 ft wide.

Who owns I-90 over W Snoqualmie Ic?

It is owned by the State Highway Agency.