RD 9117 over Twelvemile Creek
FairMineral County, Montana · Cabin City Cg · Structure no. 011607000000178
- Built
- 1963
- 62 years old
- Condition
- Fair
- inspected July 2023
- Type
- Stringer/Multi-beam or Girder
- Wood or Timber
- Length
- 31 ft
- 1 main span
- Daily traffic
- 50
- Owner
- Federal
- U.S. Forest Service
About this bridge
RD 9117 over Twelvemile Creek is a wood or timber stringer/multi-beam or girder carrying RD 9117 over Twelvemile Creek in Mineral County, Montana. It was built in 1963, so it is 62 years old, older than the Montana average of 47 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 50 vehicles a day, projected to reach 75 by 2045. The structure is 31 ft (9.3 m) long and 25 ft wide. If it were closed, the detour would be 98.2 mi (158 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 | 7 Good | Some minor problems. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was RD 9117 over Twelvemile Creek built?
It was built in 1963, making it 62 years old in 2025.
What condition is RD 9117 over Twelvemile Creek 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 July 2023.
How much traffic does RD 9117 over Twelvemile Creek carry?
About 50 vehicles per day (latest count).
How long is RD 9117 over Twelvemile Creek?
The structure is 31 ft (9.3 m) long with a longest span of 29 ft (8.8 m) and a deck 25 ft wide.
Who owns RD 9117 over Twelvemile Creek?
It is owned by the U.S. Forest Service.