I-405 over SR 522 Sammamish R
FairKing County, Washington · 8.7 N JCT SR 520 · Structure no. 0008382B0000000
- Built
- 1968
- 57 years old, rebuilt 1997
- Condition
- Fair
- inspected November 2024
- Type
- Box Beam or Girders - Multiple
- Concrete Continuous
- Length
- 1,410 ft
- 13 main spans
- Daily traffic
- 56,311
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I-405 over SR 522 Sammamish R is a concrete continuous box beam or girders - multiple carrying I-405 over SR 522 Sammamish R in King County, Washington. It was built in 1968 and reconstructed in 1997, so it is 57 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 56,311 vehicles a day, roughly 6% of them trucks, projected to reach 86,175 by 2039. The structure is 1,410 ft (429.8 m) long and 43 ft wide. If it were closed, the detour would be 1.2 mi (2 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was I-405 over SR 522 Sammamish R built?
It was built in 1968, making it 57 years old in 2025. It was reconstructed in 1997.
What condition is I-405 over SR 522 Sammamish R 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-405 over SR 522 Sammamish R carry?
About 56,311 vehicles per day (2023 count), of which roughly 6% are trucks.
How long is I-405 over SR 522 Sammamish R?
The structure is 1,410 ft (429.8 m) long with a longest span of 122 ft (37.2 m) and a deck 43 ft wide.
Who owns I-405 over SR 522 Sammamish R?
It is owned by the State Highway Agency.