US 521 NB over Twelve Mile Creek
FairLancaster County, South Carolina · 12.0 MI N Lancaster · Structure no. 000000000006997
- Built
- 1977
- 48 years old
- Condition
- Fair
- inspected September 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 284 ft
- 2 main spans
- Daily traffic
- 12,150
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
US 521 NB over Twelve Mile Creek is a prestressed concrete stringer/multi-beam or girder carrying US 521 NB over Twelve Mile Creek in Lancaster County, South Carolina. It was built in 1977, so it is 48 years old, younger 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.
It carries about 12,150 vehicles a day, roughly 6% of them trucks, projected to reach 15,917 by 2043. The structure is 284 ft (86.6 m) long and 43 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. |
| 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 US 521 NB over Twelve Mile Creek built?
It was built in 1977, making it 48 years old in 2025.
What condition is US 521 NB over Twelve Mile Creek 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 September 2024.
How much traffic does US 521 NB over Twelve Mile Creek carry?
About 12,150 vehicles per day (2023 count), of which roughly 6% are trucks.
How long is US 521 NB over Twelve Mile Creek?
The structure is 284 ft (86.6 m) long with a longest span of 43 ft (13.1 m) and a deck 43 ft wide.
Who owns US 521 NB over Twelve Mile Creek?
It is owned by the State Highway Agency.