Seward Highway over Twenty Mile River
GoodAnchorage Municipality, Alaska · Mile Point 79.9 · Structure no. 0634
- Built
- 2023
- 2 years old
- Condition
- Good
- inspected February 2024
- Type
- Tee Beam
- Prestressed Concrete
- Length
- 653 ft
- 5 main spans
- Daily traffic
- 5,200
- 2020 count
- Owner
- State
- State Highway Agency
About this bridge
Seward Highway over Twenty Mile River is a prestressed concrete tee beam carrying Seward Highway over Twenty Mile River in Anchorage Municipality, Alaska. It was built in 2023, so it is 2 years old, younger than the Alaska average of 35.9 years.
The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 9 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 5,200 vehicles a day, roughly 14% of them trucks, projected to reach 7,000 by 2035. The structure is 653 ft (198.9 m) long and 54 ft wide. If it were closed, the detour would be 123.7 mi (199 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 | 9 Excellent | No problems noted. |
| Superstructure | 9 Excellent | No problems noted. |
| Substructure | 9 Excellent | No problems noted. |
| Channel and channel protection | 9 Excellent | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Seward Highway over Twenty Mile River built?
It was built in 2023, making it 2 years old in 2025.
What condition is Seward Highway over Twenty Mile River 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 February 2024.
How much traffic does Seward Highway over Twenty Mile River carry?
About 5,200 vehicles per day (2020 count), of which roughly 14% are trucks.
How long is Seward Highway over Twenty Mile River?
The structure is 653 ft (198.9 m) long with a longest span of 127 ft (38.7 m) and a deck 54 ft wide.
Who owns Seward Highway over Twenty Mile River?
It is owned by the State Highway Agency.