US Bridges

Prater RD over I-90

Good

Kittitas County, Washington · 7.0 E JCT I-82 · Structure no. 0008386B0000000

Built
1968
57 years old
Condition
Good
inspected July 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
230 ft
2 main spans
Daily traffic
188
2002 count
Owner
State
State Highway Agency

About this bridge

Prater RD over I-90 is a prestressed concrete continuous stringer/multi-beam or girder carrying Prater RD over I-90 in Kittitas County, Washington. It was built in 1968, so it is 57 years old, older 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 188 vehicles a day, roughly 24% of them trucks, projected to reach 265 by 2036. The structure is 230 ft (70.1 m) long and 31 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesPrater RD
CrossesI-90
Location7.0 E JCT I-82
RouteCounty Highway 0
CountyKittitas County
StateWashington
Coordinates46.97215, -120.36371
Functional classRural Minor Collector

Condition and inspection

Good

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

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionJuly 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 rating82 US tons
Inventory rating48.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20 + Mod
Structure length230 ft (70.1 m)
Longest span113 ft (34.4 m)
Deck width31 ft (9.4 m)
Roadway width28 ft (8.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic188 (2002)
Projected traffic265 by 2036
Trucks24%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

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$3.3 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was Prater RD over I-90 built?

It was built in 1968, making it 57 years old in 2025.

What condition is Prater RD over I-90 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 2023.

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

About 188 vehicles per day (2002 count), of which roughly 24% are trucks.

How long is Prater RD over I-90?

The structure is 230 ft (70.1 m) long with a longest span of 113 ft (34.4 m) and a deck 31 ft wide.

Who owns Prater RD over I-90?

It is owned by the State Highway Agency.