I-405 over SR 520
GoodKing County, Washington · 3.7 N JCT I-90 · Structure no. 0007596D0000000
- Built
- 1966
- 59 years old, rebuilt 1993
- Condition
- Good
- inspected April 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 241 ft
- 4 main spans
- Daily traffic
- 67,108
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I-405 over SR 520 is a prestressed concrete stringer/multi-beam or girder carrying I-405 over SR 520 in King County, Washington. It was built in 1966 and reconstructed in 1993, so it is 59 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 67,108 vehicles a day, roughly 6% of them trucks, projected to reach 105,460 by 2039. The structure is 241 ft (73.5 m) long and 89 ft wide. If it were closed, the detour would be 1.2 mi (2 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was I-405 over SR 520 built?
It was built in 1966, making it 59 years old in 2025. It was reconstructed in 1993.
What condition is I-405 over SR 520 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 April 2024.
How much traffic does I-405 over SR 520 carry?
About 67,108 vehicles per day (2023 count), of which roughly 6% are trucks.
How long is I-405 over SR 520?
The structure is 241 ft (73.5 m) long with a longest span of 73 ft (22.3 m) and a deck 89 ft wide.
Who owns I-405 over SR 520?
It is owned by the State Highway Agency.