Mo 21 S over Rock CR
FairJefferson County, Missouri · S 1974 T 43 N R 5 E · Structure no. 2543
- Built
- 1987
- 38 years old
- Condition
- Fair
- inspected November 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete Continuous
- Length
- 291 ft
- 5 main spans
- Daily traffic
- 11,035
- 2024 count
- Owner
- State
- State Highway Agency
About this bridge
Mo 21 S over Rock CR is a prestressed concrete continuous stringer/multi-beam or girder carrying Mo 21 S over Rock CR in Jefferson County, Missouri. It was built in 1987, so it is 38 years old, younger than the Missouri average of 45.1 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 11,035 vehicles a day, roughly 4% of them trucks, projected to reach 20,415 by 2044. The structure is 291 ft (88.7 m) long and 42 ft wide. If it were closed, the detour would be 0.6 mi (1 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 | 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 Mo 21 S over Rock CR built?
It was built in 1987, making it 38 years old in 2025.
What condition is Mo 21 S over Rock CR 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 November 2024.
How much traffic does Mo 21 S over Rock CR carry?
About 11,035 vehicles per day (2024 count), of which roughly 4% are trucks.
How long is Mo 21 S over Rock CR?
The structure is 291 ft (88.7 m) long with a longest span of 59 ft (18 m) and a deck 42 ft wide.
Who owns Mo 21 S over Rock CR?
It is owned by the State Highway Agency.