I 15 over Int Monida S 509
PoorBeaverhead County, Montana · Monida · Structure no. I00015000+05201
- Built
- 1959
- 66 years old
- Condition
- Poor
- inspected October 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 118 ft
- 3 main spans
- Daily traffic
- 1,771
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I 15 over Int Monida S 509 is a prestressed concrete stringer/multi-beam or girder carrying I 15 over Int Monida S 509 in Beaverhead County, Montana. It was built in 1959, so it is 66 years old, older than the Montana average of 47 years.
The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
It carries about 1,771 vehicles a day, roughly 30% of them trucks, projected to reach 1,894 by 2043. The structure is 118 ft (36 m) long and 46 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 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 4 Poor | Advanced section loss, deterioration, spalling or scour. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was I 15 over Int Monida S 509 built?
It was built in 1959, making it 66 years old in 2025.
What condition is I 15 over Int Monida S 509 in?
The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in October 2024.
How much traffic does I 15 over Int Monida S 509 carry?
About 1,771 vehicles per day (2023 count), of which roughly 30% are trucks.
How long is I 15 over Int Monida S 509?
The structure is 118 ft (36 m) long with a longest span of 45 ft (13.7 m) and a deck 46 ft wide.
Who owns I 15 over Int Monida S 509?
It is owned by the State Highway Agency.