US Bridges

I-5 over 6th-S Ramp Br

Fair

King County, Washington · 5.5 N JCT SR 900 · Structure no. 0007741O0000000

Built
1967
58 years old
Condition
Fair
inspected November 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
424 ft
4 main spans
Daily traffic
6,076
2012 count
Owner
State
State Highway Agency

About this bridge

I-5 over 6th-S Ramp Br is a concrete continuous box beam or girders - multiple carrying I-5 over 6th-S Ramp Br 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 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 6,076 vehicles a day, roughly 5% of them trucks, projected to reach 10,159 by 2036. The structure is 424 ft (129.2 m) long and 26 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesI-5
Crosses6th-S Ramp Br
Location5.5 N JCT SR 900
RouteInterstate 5
CountyKing County
StateWashington
Coordinates47.57108, -122.324
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating40 US tons
Inventory rating30.8 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4 (+5 approach)
Design loadHS 20
Structure length424 ft (129.2 m)
Longest span90 ft (27.4 m)
Deck width26 ft (7.8 m)
Roadway width21 ft (6.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,076 (2012)
Projected traffic10,159 by 2036
Trucks5%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
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$6.2 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-5 over 6th-S Ramp Br built?

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

What condition is I-5 over 6th-S Ramp Br 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 November 2024.

How much traffic does I-5 over 6th-S Ramp Br carry?

About 6,076 vehicles per day (2012 count), of which roughly 5% are trucks.

How long is I-5 over 6th-S Ramp Br?

The structure is 424 ft (129.2 m) long with a longest span of 90 ft (27.4 m) and a deck 26 ft wide.

Who owns I-5 over 6th-S Ramp Br?

It is owned by the State Highway Agency.