US Bridges

County RD No 6 over I-90

Good

Kittitas County, Washington · 0.6 E JCT I-82 · Structure no. 0008385D0000000

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
2,030
2002 count
Owner
State
State Highway Agency

About this bridge

County RD No 6 over I-90 is a prestressed concrete continuous stringer/multi-beam or girder carrying County RD No 6 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 2,030 vehicles a day, roughly 24% of them trucks, projected to reach 3,065 by 2036. The structure is 230 ft (70.1 m) long and 31 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

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CarriesCounty RD No 6
CrossesI-90
Location0.6 E JCT I-82
RouteCounty Highway 0
CountyKittitas County
StateWashington
Coordinates46.97031, -120.49811
Functional classRural Major 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 geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment8: Equal to present desirable criteria
Operating rating75.9 US tons
Inventory rating45 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 span110 ft (33.5 m)
Deck width31 ft (9.4 m)
Roadway width28 ft (8.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,030 (2002)
Projected traffic3,065 by 2036
Trucks24%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed8.1 mi (13 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 County RD No 6 over I-90 built?

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

What condition is County RD No 6 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 County RD No 6 over I-90 carry?

About 2,030 vehicles per day (2002 count), of which roughly 24% are trucks.

How long is County RD No 6 over I-90?

The structure is 230 ft (70.1 m) long with a longest span of 110 ft (33.5 m) and a deck 31 ft wide.

Who owns County RD No 6 over I-90?

It is owned by the State Highway Agency.