Mo 21 N over Rock CR
GoodJefferson County, Missouri · S 1974 T 43 N R 5 E · Structure no. 2542
- Built
- 1987
- 38 years old
- Condition
- Good
- inspected November 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete Continuous
- Length
- 277 ft
- 5 main spans
- Daily traffic
- 11,681
- 2024 count
- Owner
- State
- State Highway Agency
About this bridge
Mo 21 N over Rock CR is a prestressed concrete continuous stringer/multi-beam or girder carrying Mo 21 N 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 good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 11,681 vehicles a day, roughly 4% of them trucks, projected to reach 21,610 by 2044. The structure is 277 ft (84.4 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
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| 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 N over Rock CR built?
It was built in 1987, making it 38 years old in 2025.
What condition is Mo 21 N over Rock CR in?
The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in November 2024.
How much traffic does Mo 21 N over Rock CR carry?
About 11,681 vehicles per day (2024 count), of which roughly 4% are trucks.
How long is Mo 21 N over Rock CR?
The structure is 277 ft (84.4 m) long with a longest span of 56 ft (17.1 m) and a deck 42 ft wide.
Who owns Mo 21 N over Rock CR?
It is owned by the State Highway Agency.