US Bridges

I-405 Ramp over Southcenter Blvd

Good

King County, Washington · 0.9 N JCT I-5 · Structure no. 0014269A0000000

Built
1994
31 years old
Condition
Good
inspected June 2021
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
185 ft
3 main spans
Daily traffic
7,007
2022 count
Owner
State
State Highway Agency

About this bridge

I-405 Ramp over Southcenter Blvd is a concrete continuous box beam or girders - multiple carrying I-405 Ramp over Southcenter Blvd in King County, Washington. It was built in 1994, so it is 31 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 7,007 vehicles a day, roughly 5% of them trucks, projected to reach 10,246 by 2039. The structure is 185 ft (56.4 m) long and 36 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesI-405 Ramp
CrossesSouthcenter Blvd
Location0.9 N JCT I-5
RouteInterstate 405
CountyKing County
StateWashington
Coordinates47.46386, -122.24756
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.
Substructure8 Very GoodNo problems noted.
Last inspectionJune 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating99 US tons
Inventory rating83 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 25 or greater
Structure length185 ft (56.4 m)
Longest span84 ft (25.6 m)
Deck width36 ft (11.1 m)
Roadway width34 ft (10.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,007 (2022)
Projected traffic10,246 by 2039
Trucks5%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed3.1 mi (5 km)
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$2.7 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-405 Ramp over Southcenter Blvd built?

It was built in 1994, making it 31 years old in 2025.

What condition is I-405 Ramp over Southcenter Blvd 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 June 2021.

How much traffic does I-405 Ramp over Southcenter Blvd carry?

About 7,007 vehicles per day (2022 count), of which roughly 5% are trucks.

How long is I-405 Ramp over Southcenter Blvd?

The structure is 185 ft (56.4 m) long with a longest span of 84 ft (25.6 m) and a deck 36 ft wide.

Who owns I-405 Ramp over Southcenter Blvd?

It is owned by the State Highway Agency.