US Bridges

SR 18 over Cedar River SE Bain RD

Fair

King County, Washington · 5.2 N JCT SR 516 · Structure no. 0016611B0000000

Built
2004
21 years old
Condition
Fair
inspected February 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
351 ft
3 main spans
Daily traffic
16,971
2023 count
Owner
State
State Highway Agency

About this bridge

SR 18 over Cedar River SE Bain RD is a prestressed concrete continuous stringer/multi-beam or girder carrying SR 18 over Cedar River SE Bain RD in King County, Washington. It was built in 2004, so it is 21 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 16,971 vehicles a day, roughly 14% of them trucks, projected to reach 24,962 by 2039. The structure is 351 ft (107 m) long and 49 ft wide.

Location

Open in Google Maps
CarriesSR 18
CrossesCedar River SE Bain RD
Location5.2 N JCT SR 516
RouteState Highway 18
CountyKing County
StateWashington
Coordinates47.40619, -122.04206
Functional classUrban Principal Arterial - Other Freeway or Expressway

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating96 US tons
Inventory rating57 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length351 ft (107 m)
Longest span125 ft (38.1 m)
Deck width49 ft (14.8 m)
Roadway width46 ft (14 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,971 (2023)
Projected traffic24,962 by 2039
Trucks14%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and waterway
Detour if closed—
TollOn a free road
National Highway SystemYes

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$8 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 18 over Cedar River SE Bain RD built?

It was built in 2004, making it 21 years old in 2025.

What condition is SR 18 over Cedar River SE Bain RD 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 February 2023.

How much traffic does SR 18 over Cedar River SE Bain RD carry?

About 16,971 vehicles per day (2023 count), of which roughly 14% are trucks.

How long is SR 18 over Cedar River SE Bain RD?

The structure is 351 ft (107 m) long with a longest span of 125 ft (38.1 m) and a deck 49 ft wide.

Who owns SR 18 over Cedar River SE Bain RD?

It is owned by the State Highway Agency.