US 17 Alt over Calfpen Swamp
Colleton County, South Carolina · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 17 Alt over Calfpen Swamp in Colleton County, South Carolina, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1925, making it 100 years old at the 2025 inventory.
- It carries about 1,350 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 149 of the 231 inventoried bridges in Colleton County rated fair (64.5%); 6 (2.6%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its class is unchanged from 2024 (fair), but component ratings moved: culvert 6 to 5.
- Its most recent inspection on record is dated March 2024, on a 24-month routine inspection cycle.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (32.75515, -80.74125)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Culvert | 6 | 5 | Fair condition |
Bridge details
| Structure | Concrete culvert |
| Length | about 22 ft |
| Location | Hendersonville |
| NBI structure number | 000000000000175 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | March 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Carolina department of transportation.
Busiest bridges in Colleton County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-95 NB over Combahee River | 1970 | 26,000 | Fair |
| I-95 NB over Combahee Swamp | 1970 | 26,000 | Fair |
| I-95 SB over Combahee River | 1970 | 26,000 | Fair |
| I-95 SB over Combahee Swamp | 1970 | 26,000 | Fair |
| I-95 NB over Great Swamp | 1972 | 24,700 | Fair |
| I-95 NB over S.c.l. Railroad | 1972 | 24,700 | Fair |
All bridges nearby: Colleton County, SC bridge conditions · every bridge in Colleton County · South Carolina bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.