US 321 over I-20
Richland County, South Carolina · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 321 over I-20 in Richland County, South Carolina, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1965, making it 60 years old at the 2025 inventory.
- It carries about 9,000 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 168 of the 367 inventoried bridges in Richland County rated fair (45.8%); 17 (4.6%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated January 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 → (34.06639, -81.0225)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 265 ft |
| Location | 5MI N of Columbia |
| NBI structure number | 000000000004653 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | January 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Carolina department of transportation.
Busiest bridges in Richland County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-26 over I-20 | 1964 | 143,200 | Fair |
| I-26/RAMP Off I-26 over RR Csxt | 1958 | 130,700 | Fair |
| I-20 over Crane Creek & S-43 | 1964 | 123,700 | Fair |
| I-20 over Broad River | 1965 | 123,700 | Fair |
| I-20 over Sou. RR & Priv. Rd. . | 1965 | 123,700 | Fair |
| I-20 over Trib to Crane Creek | 1965 | 107,900 | Fair |
All bridges nearby: Richland County, SC bridge conditions · every bridge in Richland County · South Carolina bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.