US Bridges

I-405 N-E Ramp over Northup Way

Good

King County, Washington · 4.2 N JCT I-90 · Structure no. 0017726E0000000

Built
2011
14 years old
Condition
Good
inspected August 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
332 ft
2 main spans
Daily traffic
5,000
2010 count
Owner
State
State Highway Agency

About this bridge

I-405 N-E Ramp over Northup Way is a prestressed concrete continuous stringer/multi-beam or girder carrying I-405 N-E Ramp over Northup Way in King County, Washington. It was built in 2011, so it is 14 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 5,000 vehicles a day, roughly 3% of them trucks, projected to reach 8,640 by 2036. The structure is 332 ft (101.2 m) long and 27 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesI-405 N-E Ramp
CrossesNorthup Way
Location4.2 N JCT I-90
RouteInterstate 405
CountyKing County
StateWashington
Coordinates47.63175, -122.18094
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
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation8: Equal to present desirable criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating51.5 US tons
Inventory rating39.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHL 93
Structure length332 ft (101.2 m)
Longest span171 ft (52.1 m)
Deck width27 ft (8.2 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,000 (2010)
Projected traffic8,640 by 2036
Trucks3%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed3.1 mi (5 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 statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$4.1 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-405 N-E Ramp over Northup Way built?

It was built in 2011, making it 14 years old in 2025.

What condition is I-405 N-E Ramp over Northup Way 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 August 2024.

How much traffic does I-405 N-E Ramp over Northup Way carry?

About 5,000 vehicles per day (2010 count), of which roughly 3% are trucks.

How long is I-405 N-E Ramp over Northup Way?

The structure is 332 ft (101.2 m) long with a longest span of 171 ft (52.1 m) and a deck 27 ft wide.

Who owns I-405 N-E Ramp over Northup Way?

It is owned by the State Highway Agency.