US Bridges

I-5 over SR 529 NB Ramp

Fair

Snohomish County, Washington · 4.4 N JCT US 2 · Structure no. 0008372A0000000

Built
1968
57 years old
Condition
Fair
inspected February 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
245 ft
3 main spans
Daily traffic
64,989
2023 count
Owner
State
State Highway Agency

About this bridge

I-5 over SR 529 NB Ramp is a prestressed concrete stringer/multi-beam or girder carrying I-5 over SR 529 NB Ramp in Snohomish County, Washington. It was built in 1968, 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 64,989 vehicles a day, roughly 6% of them trucks, projected to reach 95,649 by 2039. The structure is 245 ft (74.7 m) long and 55 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-5
CrossesSR 529 NB Ramp
Location4.4 N JCT US 2
RouteInterstate 5
CountySnohomish County
StateWashington
Coordinates48.04014, -122.179
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating19.3 US tons
Inventory rating15 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length245 ft (74.7 m)
Longest span94 ft (28.7 m)
Deck width55 ft (16.9 m)
Roadway width52 ft (15.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic64,989 (2023)
Projected traffic95,649 by 2039
Trucks6%
Lanes on structure3
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$5 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-5 over SR 529 NB Ramp built?

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

What condition is I-5 over SR 529 NB Ramp 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 February 2024.

How much traffic does I-5 over SR 529 NB Ramp carry?

About 64,989 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is I-5 over SR 529 NB Ramp?

The structure is 245 ft (74.7 m) long with a longest span of 94 ft (28.7 m) and a deck 55 ft wide.

Who owns I-5 over SR 529 NB Ramp?

It is owned by the State Highway Agency.