South Tongass HWY over Tongass Avenue Viaduct
FairKetchikan Gateway Borough, Alaska · Mile Point 1.3 · Structure no. 0997
- Built
- 1956
- 69 years old
- Condition
- Fair
- inspected June 2023
- Type
- Tee Beam
- Prestressed Concrete
- Length
- 1,727 ft
- 58 main spans
- Daily traffic
- 14,564
- 2018 count
- Owner
- State
- State Highway Agency
About this bridge
South Tongass HWY over Tongass Avenue Viaduct is a prestressed concrete tee beam carrying South Tongass HWY over Tongass Avenue Viaduct in Ketchikan Gateway Borough, Alaska. It was built in 1956, so it is 69 years old, older than the Alaska average of 35.9 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 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 14,564 vehicles a day, roughly 8% of them trucks, projected to reach 21,300 by 2035. The structure is 1,727 ft (526.4 m) long and 53 ft wide. If it were closed, the detour would be 5 mi (8 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 | 7 Good | Some minor problems. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Channel and channel protection | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was South Tongass HWY over Tongass Avenue Viaduct built?
It was built in 1956, making it 69 years old in 2025.
What condition is South Tongass HWY over Tongass Avenue Viaduct 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 June 2023.
How much traffic does South Tongass HWY over Tongass Avenue Viaduct carry?
About 14,564 vehicles per day (2018 count), of which roughly 8% are trucks.
How long is South Tongass HWY over Tongass Avenue Viaduct?
The structure is 1,727 ft (526.4 m) long with a longest span of 42 ft (12.8 m) and a deck 53 ft wide.
Who owns South Tongass HWY over Tongass Avenue Viaduct?
It is owned by the State Highway Agency.