US101 (hwy 9) over Half Viaduct
GoodTillamook County, Oregon · 025 MI N Manzanita · Structure no. 01953 009 04075
- Built
- 1940
- 85 years old
- Condition
- Good
- inspected October 2024
- Type
- Tee Beam
- Concrete Continuous
- Length
- 90 ft
- 6 main spans
- Daily traffic
- 5,743
- 2022 count
- Owner
- State
- State Highway Agency
About this bridge
US101 (hwy 9) over Half Viaduct is a concrete continuous tee beam carrying US101 (hwy 9) over Half Viaduct in Tillamook County, Oregon. It was built in 1940, so it is 85 years old, older than the Oregon average of 49.9 years.
The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 5,743 vehicles a day, roughly 12% of them trucks, projected to reach 7,560 by 2042. The structure is 90 ft (27.4 m) long and 24 ft wide. If it were closed, the detour would be 6.2 mi (10 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 | 8 Very Good | No problems noted. |
| Superstructure | 8 Very Good | No problems noted. |
| Substructure | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was US101 (hwy 9) over Half Viaduct built?
It was built in 1940, making it 85 years old in 2025.
What condition is US101 (hwy 9) over Half Viaduct 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 October 2024.
How much traffic does US101 (hwy 9) over Half Viaduct carry?
About 5,743 vehicles per day (2022 count), of which roughly 12% are trucks.
How long is US101 (hwy 9) over Half Viaduct?
The structure is 90 ft (27.4 m) long with a longest span of 15 ft (4.6 m) and a deck 24 ft wide.
Who owns US101 (hwy 9) over Half Viaduct?
It is owned by the State Highway Agency.