US Bridges

SR 18 E-N Ramp over I-5 SR 18 Ramps

Fair

King County, Washington · JCT I-5 · Structure no. 0017936A0000000

Built
2012
13 years old
Condition
Fair
inspected July 2024
Type
Box Beam or Girders - Single or Spread
Steel Continuous
Length
1,449 ft
4 main spans
Daily traffic
15,430
2023 count
Owner
State
State Highway Agency

About this bridge

SR 18 E-N Ramp over I-5 SR 18 Ramps is a steel continuous box beam or girders - single or spread carrying SR 18 E-N Ramp over I-5 SR 18 Ramps in King County, Washington. It was built in 2012, so it is 13 years old, younger 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 15,430 vehicles a day, roughly 12% of them trucks, projected to reach 22,147 by 2039. The structure is 1,449 ft (441.7 m) long and 29 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesSR 18 E-N Ramp
CrossesI-5 SR 18 Ramps
LocationJCT I-5
RouteState Highway 18
CountyKing County
StateWashington
Coordinates47.28811, -122.30808
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.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation8: Equal to present desirable criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48.2 US tons
Inventory rating37.1 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4 (+6 approach)
Design loadHL 93
Structure length1,449 ft (441.7 m)
Longest span186 ft (56.7 m)
Deck width29 ft (8.8 m)
Roadway width27 ft (8.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15,430 (2023)
Projected traffic22,147 by 2039
Trucks12%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 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$20 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 18 E-N Ramp over I-5 SR 18 Ramps built?

It was built in 2012, making it 13 years old in 2025.

What condition is SR 18 E-N Ramp over I-5 SR 18 Ramps 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 July 2024.

How much traffic does SR 18 E-N Ramp over I-5 SR 18 Ramps carry?

About 15,430 vehicles per day (2023 count), of which roughly 12% are trucks.

How long is SR 18 E-N Ramp over I-5 SR 18 Ramps?

The structure is 1,449 ft (441.7 m) long with a longest span of 186 ft (56.7 m) and a deck 29 ft wide.

Who owns SR 18 E-N Ramp over I-5 SR 18 Ramps?

It is owned by the State Highway Agency.