US Bridges

O.K. Mill RD over Pilchuck River

Good

Snohomish County, Washington · 3.5 S JCT SR92 · Structure no. 087277000000000

Built
2005
20 years old
Condition
Good
inspected June 2024
Type
Truss - Thru
Steel
Length
244 ft
1 main span
Daily traffic
8,197
2021 count
Owner
County
County Highway Agency

About this bridge

O.K. Mill RD over Pilchuck River is a steel truss - thru carrying O.K. Mill RD over Pilchuck River in Snohomish County, Washington. It was built in 2005, so it is 20 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 8,197 vehicles a day, roughly 13% of them trucks, projected to reach 12,000 by 2042. The structure is 244 ft (74.4 m) long and 47 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

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CarriesO.K. Mill RD
CrossesPilchuck River
Location3.5 S JCT SR92
RouteCounty Highway 94555
CountySnohomish County
StateWashington
Coordinates47.98682, -122.03624
Functional classUrban Minor Arterial

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.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than 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 alignment8: Equal to present desirable criteria
Operating rating84 US tons
Inventory rating50 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHL 93
Structure length244 ft (74.4 m)
Longest span236 ft (71.9 m)
Deck width47 ft (14.4 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deck25 ft (7.8 m)

Traffic and service

Average daily traffic8,197 (2021)
Projected traffic12,000 by 2042
Trucks13%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$4.9 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was O.K. Mill RD over Pilchuck River built?

It was built in 2005, making it 20 years old in 2025.

What condition is O.K. Mill RD over Pilchuck River 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 O.K. Mill RD over Pilchuck River carry?

About 8,197 vehicles per day (2021 count), of which roughly 13% are trucks.

How long is O.K. Mill RD over Pilchuck River?

The structure is 244 ft (74.4 m) long with a longest span of 236 ft (71.9 m) and a deck 47 ft wide.

Who owns O.K. Mill RD over Pilchuck River?

It is owned by the County Highway Agency.