Mo 21 S over Big Rvr
GoodJefferson County, Missouri · S 26 T 39 N R 3 E · Structure no. 3529
- Built
- 1985
- 40 years old
- Condition
- Good
- inspected December 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete Continuous
- Length
- 321 ft
- 4 main spans
- Daily traffic
- 7,193
- 2024 count
- Owner
- State
- State Highway Agency
About this bridge
Mo 21 S over Big Rvr is a prestressed concrete continuous stringer/multi-beam or girder carrying Mo 21 S over Big Rvr in Jefferson County, Missouri. It was built in 1985, so it is 40 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 7,193 vehicles a day, roughly 7% of them trucks, projected to reach 13,307 by 2044. The structure is 321 ft (97.8 m) long and 41 ft wide. If it were closed, the detour would be 51 mi (82 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Mo 21 S over Big Rvr built?
It was built in 1985, making it 40 years old in 2025.
What condition is Mo 21 S over Big Rvr 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 December 2024.
How much traffic does Mo 21 S over Big Rvr carry?
About 7,193 vehicles per day (2024 count), of which roughly 7% are trucks.
How long is Mo 21 S over Big Rvr?
The structure is 321 ft (97.8 m) long with a longest span of 89 ft (27.1 m) and a deck 41 ft wide.
Who owns Mo 21 S over Big Rvr?
It is owned by the State Highway Agency.