US Bridges

I-90 over Silica RD

Good

Grant County, Washington · 6.1 E JCT SR 26 · Structure no. 0011975B0000000

Built
1982
43 years old
Condition
Good
inspected June 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
123 ft
1 main span
Daily traffic
8,141
2023 count
Owner
State
State Highway Agency

About this bridge

I-90 over Silica RD is a prestressed concrete stringer/multi-beam or girder carrying I-90 over Silica RD in Grant County, Washington. It was built in 1982, so it is 43 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 8,141 vehicles a day, roughly 28% of them trucks, projected to reach 9,956 by 2039. The structure is 123 ft (37.5 m) long and 41 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesI-90
CrossesSilica RD
Location6.1 E JCT SR 26
RouteInterstate 90
Coordinates47.02092, -119.94492
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 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating73 US tons
Inventory rating43 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length123 ft (37.5 m)
Longest span117 ft (35.7 m)
Deck width41 ft (12.5 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,141 (2023)
Projected traffic9,956 by 2039
Trucks28%
Lanes on structure2
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$2.4 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-90 over Silica RD built?

It was built in 1982, making it 43 years old in 2025.

What condition is I-90 over Silica RD 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 2024.

How much traffic does I-90 over Silica RD carry?

About 8,141 vehicles per day (2023 count), of which roughly 28% are trucks.

How long is I-90 over Silica RD?

The structure is 123 ft (37.5 m) long with a longest span of 117 ft (35.7 m) and a deck 41 ft wide.

Who owns I-90 over Silica RD?

It is owned by the State Highway Agency.