Mo 21 S over Is 270
FairPosted for loadSt. Louis County, Missouri · S 1998 T 44 N R 6 E · Structure no. 829
- Built
- 1967
- 58 years old, rebuilt 1996
- Condition
- Fair
- inspected July 2024
- Type
- Stringer/Multi-beam or Girder
- Steel Continuous
- Length
- 260 ft
- 4 main spans
- Daily traffic
- 36,433
- 2024 count
- Owner
- State
- State Highway Agency
About this bridge
Mo 21 S over Is 270 is a steel continuous stringer/multi-beam or girder carrying Mo 21 S over Is 270 in St. Louis County, Missouri. It was built in 1967 and reconstructed in 1996, so it is 58 years old, older 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. Its operating status is: posted for load restriction.
It carries about 36,433 vehicles a day, roughly 5% of them trucks, projected to reach 51,006 by 2044. The structure is 260 ft (79.2 m) long and 139 ft wide. If it were closed, the detour would be 1.2 mi (2 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 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 Is 270 built?
It was built in 1967, making it 58 years old in 2025. It was reconstructed in 1996.
What condition is Mo 21 S over Is 270 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 2024.
How much traffic does Mo 21 S over Is 270 carry?
About 36,433 vehicles per day (2024 count), of which roughly 5% are trucks.
How long is Mo 21 S over Is 270?
The structure is 260 ft (79.2 m) long with a longest span of 78 ft (23.8 m) and a deck 139 ft wide.
Who owns Mo 21 S over Is 270?
It is owned by the State Highway Agency.