US Bridges

SQUAW/3660 over Squaw Creek

Fair

Whitman County, Washington · 1.15 MI SE Spkn Cnty Line · Structure no. 080623000000000

Built
1979
46 years old
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
30 ft
1 main span
Daily traffic
57
2021 count
Owner
County
County Highway Agency

About this bridge

SQUAW/3660 over Squaw Creek is a prestressed concrete stringer/multi-beam or girder carrying SQUAW/3660 over Squaw Creek in Whitman County, Washington. It was built in 1979, so it is 46 years old, younger 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 6 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 57 vehicles a day, roughly 25% of them trucks, projected to reach 58 by 2044. The structure is 30 ft (9.1 m) long and 24 ft wide. If it were closed, the detour would be 19.3 mi (31 km).

CarriesSQUAW/3660
CrossesSquaw Creek
Location1.15 MI SE Spkn Cnty Line
RouteCounty Highway 36600
Coordinates47.2501, -117.43727
Functional classRural Local

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating41.8 US tons
Inventory rating23.9 US tons

Structure

MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadHS 20
Structure length30 ft (9.1 m)
Longest span29 ft (8.8 m)
Deck width24 ft (7.3 m)
Roadway width24 ft (7.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic57 (2021)
Projected traffic58 by 2044
Trucks25%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed19.3 mi (31 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.4 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SQUAW/3660 over Squaw Creek built?

It was built in 1979, making it 46 years old in 2025.

What condition is SQUAW/3660 over Squaw Creek 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 November 2023.

How much traffic does SQUAW/3660 over Squaw Creek carry?

About 57 vehicles per day (2021 count), of which roughly 25% are trucks.

How long is SQUAW/3660 over Squaw Creek?

The structure is 30 ft (9.1 m) long with a longest span of 29 ft (8.8 m) and a deck 24 ft wide.

Who owns SQUAW/3660 over Squaw Creek?

It is owned by the County Highway Agency.