US Bridges

120th Ave. SE over Trib. Pilchuck River

Fair

Snohomish County, Washington · 0.5 S JCT Three Lk RD/SR2 · Structure no. 080748000000000

Built
1964
61 years old
Condition
Fair
inspected July 2023
Type
Channel Beam
Concrete
Length
23 ft
1 main span
Daily traffic
15
2019 count
Owner
County
County Highway Agency

About this bridge

120th Ave. SE over Trib. Pilchuck River is a concrete channel beam carrying 120th Ave. SE over Trib. Pilchuck River in Snohomish County, Washington. It was built in 1964, so it is 61 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 15 vehicles a day, roughly 6% of them trucks, projected to reach 50 by 2045. The structure is 23 ft (7 m) long and 24 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
Carries120th Ave. SE
CrossesTrib. Pilchuck River
Location0.5 S JCT Three Lk RD/SR2
RouteCounty Highway 46760
CountySnohomish County
StateWashington
Coordinates47.92799, -122.07204
Functional classUrban 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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating52 US tons
Inventory rating31 US tons

Structure

Structure typeChannel Beam
MaterialConcrete
DeckOther
Main spans1
Design loadH 15
Structure length23 ft (7 m)
Longest span22 ft (6.6 m)
Deck width24 ft (7.3 m)
Roadway width23 ft (6.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15 (2019)
Projected traffic50 by 2045
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 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$1.2 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was 120th Ave. SE over Trib. Pilchuck River built?

It was built in 1964, making it 61 years old in 2025.

What condition is 120th Ave. SE over Trib. Pilchuck River 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 July 2023.

How much traffic does 120th Ave. SE over Trib. Pilchuck River carry?

About 15 vehicles per day (2019 count), of which roughly 6% are trucks.

How long is 120th Ave. SE over Trib. Pilchuck River?

The structure is 23 ft (7 m) long with a longest span of 22 ft (6.6 m) and a deck 24 ft wide.

Who owns 120th Ave. SE over Trib. Pilchuck River?

It is owned by the County Highway Agency.