US Bridges

SR 18 Ramp over Soosette Creek

Good

King County, Washington · 4.7 E JCT SR 164 · Structure no. 0014776C0000000

Built
1997
28 years old
Condition
Good
inspected October 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
360 ft
3 main spans
Daily traffic
6,021
2023 count
Owner
State
State Highway Agency

About this bridge

SR 18 Ramp over Soosette Creek is a prestressed concrete continuous stringer/multi-beam or girder carrying SR 18 Ramp over Soosette Creek in King County, Washington. It was built in 1997, so it is 28 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 6,021 vehicles a day, roughly 4% of them trucks, projected to reach 8,418 by 2039. The structure is 360 ft (109.7 m) long and 28 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesSR 18 Ramp
CrossesSoosette Creek
Location4.7 E JCT SR 164
RouteState Highway 18
CountyKing County
StateWashington
Coordinates47.33168, -122.15607
Functional classUrban Principal Arterial - Other Freeway or Expressway

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.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations on dry land well above flood water elevations
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating60 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 25 or greater
Structure length360 ft (109.7 m)
Longest span128 ft (39 m)
Deck width28 ft (8.5 m)
Roadway width25 ft (7.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,021 (2023)
Projected traffic8,418 by 2039
Trucks4%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

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$4.6 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 18 Ramp over Soosette Creek built?

It was built in 1997, making it 28 years old in 2025.

What condition is SR 18 Ramp over Soosette Creek 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 October 2023.

How much traffic does SR 18 Ramp over Soosette Creek carry?

About 6,021 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is SR 18 Ramp over Soosette Creek?

The structure is 360 ft (109.7 m) long with a longest span of 128 ft (39 m) and a deck 28 ft wide.

Who owns SR 18 Ramp over Soosette Creek?

It is owned by the State Highway Agency.