US Bridges

I-405 over 228th ST

Fair

Snohomish County, Washington · 1.3 N King CO · Structure no. 0008375D0000000

Built
1968
57 years old, rebuilt 1998
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
273 ft
3 main spans
Daily traffic
46,512
2023 count
Owner
State
State Highway Agency

About this bridge

I-405 over 228th ST is a prestressed concrete continuous stringer/multi-beam or girder carrying I-405 over 228th ST in Snohomish County, Washington. It was built in 1968 and reconstructed in 1998, 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 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 46,512 vehicles a day, roughly 5% of them trucks, projected to reach 71,315 by 2039. The structure is 273 ft (83.2 m) long and 69 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-405
Crosses228th ST
Location1.3 N King CO
RouteInterstate 405
CountySnohomish County
StateWashington
Coordinates47.79114, -122.20717
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating83 US tons
Inventory rating50 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length273 ft (83.2 m)
Longest span103 ft (31.4 m)
Deck width69 ft (20.9 m)
Roadway width66 ft (20 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic46,512 (2023)
Projected traffic71,315 by 2039
Trucks5%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
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$8.6 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-405 over 228th ST built?

It was built in 1968, making it 57 years old in 2025. It was reconstructed in 1998.

What condition is I-405 over 228th ST 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 April 2023.

How much traffic does I-405 over 228th ST carry?

About 46,512 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is I-405 over 228th ST?

The structure is 273 ft (83.2 m) long with a longest span of 103 ft (31.4 m) and a deck 69 ft wide.

Who owns I-405 over 228th ST?

It is owned by the State Highway Agency.