US Bridges

I-405 Ramp over Southcenter Blvd

Good

King County, Washington · 0.9 N JCT I-5 · Structure no. 0014269B0000000

Built
1994
31 years old
Condition
Good
inspected June 2021
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
197 ft
3 main spans
Daily traffic
8,919
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 8,919 vehicles a day, roughly 5% of them trucks, projected to reach 13,041 by 2039. The structure is 197 ft (60 m) long and 28 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesI-405 Ramp
CrossesSouthcenter Blvd
Location0.9 N JCT I-5
RouteInterstate 405
CountyKing County
StateWashington
Coordinates47.46397, -122.24714
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.
Substructure7 GoodSome minor problems.
Last inspectionJune 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating89 US tons
Inventory rating53 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 25 or greater
Structure length197 ft (60 m)
Longest span91 ft (27.7 m)
Deck width28 ft (8.4 m)
Roadway width25 ft (7.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,919 (2022)
Projected traffic13,041 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 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 8,919 vehicles per day (2022 count), of which roughly 5% are trucks.

How long is I-405 Ramp over Southcenter Blvd?

The structure is 197 ft (60 m) long with a longest span of 91 ft (27.7 m) and a deck 28 ft wide.

Who owns I-405 Ramp over Southcenter Blvd?

It is owned by the State Highway Agency.