US Bridges

N-N Ramp over I-5

Good

Snohomish County, Washington · 3.1 N JCT SR 527 · Structure no. 0016991A0000000

Built
2006
19 years old
Condition
Good
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
1,323 ft
2 main spans
Daily traffic
9,786
2023 count
Owner
State
State Highway Agency

About this bridge

N-N Ramp over I-5 is a steel stringer/multi-beam or girder carrying N-N Ramp over I-5 in Snohomish County, Washington. It was built in 2006, so it is 19 years old, younger 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 9,786 vehicles a day, roughly 10% of them trucks, projected to reach 14,469 by 2039. The structure is 1,323 ft (403.3 m) long and 30 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesN-N Ramp
CrossesI-5
Location3.1 N JCT SR 527
RouteInterstate 5
CountySnohomish County
StateWashington
Coordinates47.95866, -122.19904
Functional classUrban 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.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating94 US tons
Inventory rating56 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2 (+6 approach)
Design loadHL 93
Structure length1,323 ft (403.3 m)
Longest span257 ft (78.3 m)
Deck width30 ft (9 m)
Roadway width27 ft (8.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,786 (2023)
Projected traffic14,469 by 2039
Trucks10%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$18.2 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was N-N Ramp over I-5 built?

It was built in 2006, making it 19 years old in 2025.

What condition is N-N Ramp over I-5 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 July 2023.

How much traffic does N-N Ramp over I-5 carry?

About 9,786 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is N-N Ramp over I-5?

The structure is 1,323 ft (403.3 m) long with a longest span of 257 ft (78.3 m) and a deck 30 ft wide.

Who owns N-N Ramp over I-5?

It is owned by the State Highway Agency.