US 21 Bus over Beaufort River
Beaufort County, South Carolina · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 21 Bus over Beaufort River in Beaufort County, South Carolina, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1960, making it 65 years old at the 2025 inventory.
- It carries about 15,600 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 40 of the 72 inventoried bridges in Beaufort County rated fair (55.6%); 4 (5.6%) are rated poor.
- Its traffic status in the 2025 inventory is posted for another load-capacity restriction (speed, number of vehicles on the bridge, etc.) (NBI item 41).
- Its class is unchanged from 2024 (fair), but component ratings moved: deck 7 to 6.
- Its most recent inspection on record is dated November 2024, on a 24-month routine inspection cycle.
- It has fracture-critical members (NBI item 92A): steel tension members without a redundant load path, which get their own scheduled inspections.
- 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 → (32.42772, -80.66923)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 6 | Satisfactory condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Steel movable swing |
| Length | about 2,290 ft |
| Location | In Town of Beaufort |
| NBI structure number | 000000000003186 |
| Condition class | Fair |
| Traffic status (item 41) | Posted for another load-capacity restriction (speed, number of vehicles on the bridge, etc.) |
| Last inspection (item 90) | November 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
| Fracture critical (item 92A) | Yes |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Carolina department of transportation.
Busiest bridges in Beaufort County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 278 EB over Okatie River | 1991 | 33,950 | Fair |
| US 278 EB over Sc 170 | 1991 | 33,950 | Good |
| US 278 WB over Okatie River | 1991 | 33,950 | Fair |
| US 278 WB over Sc 170 | 1991 | 33,950 | Good |
| US 21/RIBAUT Rd over Battery Creek Overflow | 1993 | 32,900 | Fair |
| US 21 over Battery Creek | 1994 | 32,900 | Fair |
All bridges nearby: Beaufort County, SC bridge conditions · every bridge in Beaufort County · South Carolina bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.