US Bridges

N-W Ramp over I-405 N-E Ramp

Good

King County, Washington · 7.9 N JCT SR 520 · Structure no. 0018204A0000000

Built
2015
10 years old
Condition
Good
inspected November 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
386 ft
3 main spans
Daily traffic
7,291
2023 count
Owner
State
State Highway Agency

About this bridge

N-W Ramp over I-405 N-E Ramp is a prestressed concrete continuous stringer/multi-beam or girder carrying N-W Ramp over I-405 N-E Ramp in King County, Washington. It was built in 2015, so it is 10 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 7,291 vehicles a day, roughly 3% of them trucks, projected to reach 9,240 by 2034. The structure is 386 ft (117.7 m) long and 60 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesN-W Ramp
CrossesI-405 N-E Ramp
Location7.9 N JCT SR 520
RouteInterstate 405
CountyKing County
StateWashington
Coordinates47.74522, -122.18633
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.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation8: Equal to present desirable criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55.3 US tons
Inventory rating42.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length386 ft (117.7 m)
Longest span132 ft (40.1 m)
Deck width60 ft (18.3 m)
Roadway width39 ft (11.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,291 (2023)
Projected traffic9,240 by 2034
Trucks3%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.9 mi (3 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 proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$9.9 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was N-W Ramp over I-405 N-E Ramp built?

It was built in 2015, making it 10 years old in 2025.

What condition is N-W Ramp over I-405 N-E Ramp 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 November 2023.

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

About 7,291 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is N-W Ramp over I-405 N-E Ramp?

The structure is 386 ft (117.7 m) long with a longest span of 132 ft (40.1 m) and a deck 60 ft wide.

Who owns N-W Ramp over I-405 N-E Ramp?

It is owned by the State Highway Agency.