S-21-86 over Big Swamp
FairPosted for loadFlorence County, South Carolina · 3.5 SE Pamplico · Structure no. 000000000005724
- Built
- 1970
- 55 years old, rebuilt 1995
- Condition
- Fair
- inspected March 2023
- Type
- Slab
- Concrete
- Length
- 105 ft
- 7 main spans
- Daily traffic
- 1,050
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
S-21-86 over Big Swamp is a concrete slab carrying S-21-86 over Big Swamp in Florence County, South Carolina. It was built in 1970 and reconstructed in 1995, so it is 55 years old, older than the South Carolina average of 48 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 1,050 vehicles a day, roughly 18% of them trucks, projected to reach 1,460 by 2043. The structure is 105 ft (32 m) long and 28 ft wide. If it were closed, the detour would be 1.9 mi (3 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| 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 S-21-86 over Big Swamp built?
It was built in 1970, making it 55 years old in 2025. It was reconstructed in 1995.
What condition is S-21-86 over Big Swamp 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 March 2023.
How much traffic does S-21-86 over Big Swamp carry?
About 1,050 vehicles per day (2023 count), of which roughly 18% are trucks.
How long is S-21-86 over Big Swamp?
The structure is 105 ft (32 m) long with a longest span of 15 ft (4.6 m) and a deck 28 ft wide.
Who owns S-21-86 over Big Swamp?
It is owned by the State Highway Agency.