US Bridges

I-405 over SR 524 (filbert Rd)

Fair

Snohomish County, Washington · 2.9 N JCT SR 527 · Structure no. 0011598A0000000

Built
1968
57 years old, rebuilt 2001
Condition
Fair
inspected June 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
341 ft
3 main spans
Daily traffic
61,143
2023 count
Owner
State
State Highway Agency

About this bridge

I-405 over SR 524 (filbert Rd) is a concrete continuous box beam or girders - multiple carrying I-405 over SR 524 (filbert Rd) in Snohomish County, Washington. It was built in 1968 and reconstructed in 2001, so it is 57 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 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 61,143 vehicles a day, roughly 5% of them trucks, projected to reach 93,782 by 2039. The structure is 341 ft (103.9 m) long and 81 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesI-405
CrossesSR 524 (filbert Rd)
Location2.9 N JCT SR 527
RouteInterstate 405
Coordinates47.82525, -122.2535
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations on dry land well above flood water elevations
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating52 US tons
Inventory rating31 US tons

Structure

MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length341 ft (103.9 m)
Longest span137 ft (41.8 m)
Deck width81 ft (24.8 m)
Roadway width79 ft (24.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic61,143 (2023)
Projected traffic93,782 by 2039
Trucks5%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and waterway
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$13.1 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-405 over SR 524 (filbert Rd) built?

It was built in 1968, making it 57 years old in 2025. It was reconstructed in 2001.

What condition is I-405 over SR 524 (filbert Rd) 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 2024.

How much traffic does I-405 over SR 524 (filbert Rd) carry?

About 61,143 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is I-405 over SR 524 (filbert Rd)?

The structure is 341 ft (103.9 m) long with a longest span of 137 ft (41.8 m) and a deck 81 ft wide.

Who owns I-405 over SR 524 (filbert Rd)?

It is owned by the State Highway Agency.