US Bridges

I-405 over SR 515

Good

King County, Washington · 0.5 N JCT SR 167 · Structure no. 0007376C0000000

Built
1964
61 years old, rebuilt 1988
Condition
Good
inspected June 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
215 ft
3 main spans
Daily traffic
45,853
2023 count
Owner
State
State Highway Agency

About this bridge

I-405 over SR 515 is a prestressed concrete stringer/multi-beam or girder carrying I-405 over SR 515 in King County, Washington. It was built in 1964 and reconstructed in 1988, so it is 61 years old, older 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 45,853 vehicles a day, roughly 6% of them trucks, projected to reach 66,729 by 2039. The structure is 215 ft (65.5 m) long and 110 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-405
CrossesSR 515
Location0.5 N JCT SR 167
RouteInterstate 405
CountyKing County
StateWashington
Coordinates47.46895, -122.20638
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 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating83 US tons
Inventory rating48.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length215 ft (65.5 m)
Longest span101 ft (30.8 m)
Deck width110 ft (33.4 m)
Roadway width108 ft (32.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic45,853 (2023)
Projected traffic66,729 by 2039
Trucks6%
Lanes on structure8
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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$11 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-405 over SR 515 built?

It was built in 1964, making it 61 years old in 2025. It was reconstructed in 1988.

What condition is I-405 over SR 515 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 2023.

How much traffic does I-405 over SR 515 carry?

About 45,853 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is I-405 over SR 515?

The structure is 215 ft (65.5 m) long with a longest span of 101 ft (30.8 m) and a deck 110 ft wide.

Who owns I-405 over SR 515?

It is owned by the State Highway Agency.