US Bridges

N-W Ramp over Railroad

Good

King County, Washington · 4.1 N JCT SR 900 · Structure no. 0007930A0000000

Built
1967
58 years old
Condition
Good
inspected April 2023
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
291 ft
3 main spans
Daily traffic
3,978
2012 count
Owner
State
State Highway Agency

About this bridge

N-W Ramp over Railroad is a concrete continuous box beam or girders - multiple carrying N-W Ramp over Railroad in King County, Washington. It was built in 1967, so it is 58 years old, older 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 3,978 vehicles a day, roughly 5% of them trucks, projected to reach 6,651 by 2036. The structure is 291 ft (88.7 m) long and 26 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesN-W Ramp
CrossesRailroad
Location4.1 N JCT SR 900
RouteInterstate 5
CountyKing County
StateWashington
Coordinates47.55267, -122.31811
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 inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating70 US tons
Inventory rating41 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length291 ft (88.7 m)
Longest span115 ft (35.1 m)
Deck width26 ft (7.8 m)
Roadway width21 ft (6.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,978 (2012)
Projected traffic6,651 by 2036
Trucks5%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes

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$4.6 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was N-W Ramp over Railroad built?

It was built in 1967, making it 58 years old in 2025.

What condition is N-W Ramp over Railroad 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 April 2023.

How much traffic does N-W Ramp over Railroad carry?

About 3,978 vehicles per day (2012 count), of which roughly 5% are trucks.

How long is N-W Ramp over Railroad?

The structure is 291 ft (88.7 m) long with a longest span of 115 ft (35.1 m) and a deck 26 ft wide.

Who owns N-W Ramp over Railroad?

It is owned by the State Highway Agency.