S 21 over Int Conrad I 15
FairPondera County, Montana · Conrad · Structure no. P00021005+01641
- Built
- 1972
- 53 years old
- Condition
- Fair
- inspected June 2023
- Type
- Stringer/Multi-beam or Girder
- Steel Continuous
- Length
- 371 ft
- 2 main spans
- Daily traffic
- 100
- 2025 count
- Owner
- State
- State Highway Agency
About this bridge
S 21 over Int Conrad I 15 is a steel continuous stringer/multi-beam or girder carrying S 21 over Int Conrad I 15 in Pondera County, Montana. It was built in 1972, so it is 53 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 100 vehicles a day, roughly 3% of them trucks, projected to reach 100 by 2040. The structure is 371 ft (113.1 m) long and 50 ft wide.
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 | 8 Very Good | No problems noted. |
| 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 S 21 over Int Conrad I 15 built?
It was built in 1972, making it 53 years old in 2025.
What condition is S 21 over Int Conrad I 15 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 S 21 over Int Conrad I 15 carry?
About 100 vehicles per day (2025 count), of which roughly 3% are trucks.
How long is S 21 over Int Conrad I 15?
The structure is 371 ft (113.1 m) long with a longest span of 122 ft (37.2 m) and a deck 50 ft wide.
Who owns S 21 over Int Conrad I 15?
It is owned by the State Highway Agency.