FM over Rock River
FairLyon County, Iowa · 100452003 · Structure no. 000000000231091
- Built
- 1980
- 45 years old
- Condition
- Fair
- inspected July 2023
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 273 ft
- 4 main spans
- Daily traffic
- 180
- 2022 count
- Owner
- County
- County Highway Agency
About this bridge
FM over Rock River is a prestressed concrete stringer/multi-beam or girder carrying FM over Rock River in Lyon County, Iowa. It was built in 1980, so it is 45 years old, younger than the Iowa average of 45.5 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 180 vehicles a day, roughly 12% of them trucks, projected to reach 180 by 2043. The structure is 273 ft (83.2 m) long and 32 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 | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was FM over Rock River built?
It was built in 1980, making it 45 years old in 2025.
What condition is FM over Rock River 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 FM over Rock River carry?
About 180 vehicles per day (2022 count), of which roughly 12% are trucks.
How long is FM over Rock River?
The structure is 273 ft (83.2 m) long with a longest span of 69 ft (21 m) and a deck 32 ft wide.
Who owns FM over Rock River?
It is owned by the County Highway Agency.