US Bridges

I-5 over Pilchuck Creek

Good

Snohomish County, Washington · 2.0 N JCT SR 530 · Structure no. 0009130B0000000

Built
1973
52 years old
Condition
Good
inspected June 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
306 ft
3 main spans
Daily traffic
41,822
2023 count
Owner
State
State Highway Agency

About this bridge

I-5 over Pilchuck Creek is a prestressed concrete continuous stringer/multi-beam or girder carrying I-5 over Pilchuck Creek in Snohomish County, Washington. It was built in 1973, so it is 52 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 41,822 vehicles a day, roughly 8% of them trucks, projected to reach 60,915 by 2039. The structure is 306 ft (93.3 m) long and 70 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-5
CrossesPilchuck Creek
Location2.0 N JCT SR 530
RouteInterstate 5
CountySnohomish County
StateWashington
Coordinates48.21411, -122.21731
Functional classRural Principal Arterial - Interstate

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 protection7 GoodSome minor problems.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
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 rating58 US tons
Inventory rating34 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length306 ft (93.3 m)
Longest span100 ft (30.5 m)
Deck width70 ft (21.2 m)
Roadway width63 ft (19.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic41,822 (2023)
Projected traffic60,915 by 2039
Trucks8%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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$10.5 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-5 over Pilchuck Creek built?

It was built in 1973, making it 52 years old in 2025.

What condition is I-5 over Pilchuck Creek 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 2023.

How much traffic does I-5 over Pilchuck Creek carry?

About 41,822 vehicles per day (2023 count), of which roughly 8% are trucks.

How long is I-5 over Pilchuck Creek?

The structure is 306 ft (93.3 m) long with a longest span of 100 ft (30.5 m) and a deck 70 ft wide.

Who owns I-5 over Pilchuck Creek?

It is owned by the State Highway Agency.