US Bridges

US 97 over Slough Br

Fair

Kittitas County, Washington · 2.5 N JCT I-90 · Structure no. 0002193A0000000

Built
1936
89 years old
Condition
Fair
inspected June 2023
Type
Slab
Concrete Continuous
Length
50 ft
2 main spans
Daily traffic
4,571
2023 count
Owner
State
State Highway Agency

About this bridge

US 97 over Slough Br is a concrete continuous slab carrying US 97 over Slough Br in Kittitas County, Washington. It was built in 1936, so it is 89 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 4,571 vehicles a day, roughly 17% of them trucks, projected to reach 5,463 by 2039. The structure is 50 ft (15.2 m) long and 30 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesUS 97
CrossesSlough Br
Location2.5 N JCT I-90
RouteU.S. Route 97
CountyKittitas County
StateWashington
Coordinates47.0326, -120.60797
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating37.5 US tons
Inventory rating28.9 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadH 15
Structure length50 ft (15.2 m)
Longest span22 ft (6.7 m)
Deck width30 ft (9.2 m)
Roadway width27 ft (8.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,571 (2023)
Projected traffic5,463 by 2039
Trucks17%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes

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$808,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 97 over Slough Br built?

It was built in 1936, making it 89 years old in 2025.

What condition is US 97 over Slough Br in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in June 2023.

How much traffic does US 97 over Slough Br carry?

About 4,571 vehicles per day (2023 count), of which roughly 17% are trucks.

How long is US 97 over Slough Br?

The structure is 50 ft (15.2 m) long with a longest span of 22 ft (6.7 m) and a deck 30 ft wide.

Who owns US 97 over Slough Br?

It is owned by the State Highway Agency.