US 21 SB
Carrying US 21 SB over BEAUFORT RIVER
SOUTHEAST OF BEAUFORT, Beaufort, South Carolina
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: US 21 SB
The US 21 SB bridge in Beaufort, South Carolina carries US 21 SB over BEAUFORT RIVER. It was built in 1979, making it 47 years old today. The structure is built primarily of steel continuous and spans 15 sections, stretching 1283.2 meters (4210 feet) end to end. Daily traffic averages 12,000 vehicles, placing it in the heavily-trafficked tier of South Carolina bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 6/9, superstructure at 6/9, substructure at 4/9. The weakest component sits in poor condition. A component scored 4 or below, placing this bridge in the federal Poor condition category rather than declaring it unsafe or closed. Its NBI inventory load rating is 13.9 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How US 21 SB compares
Live comparison across South Carolina.
Historical Sufficiency Rating
PlainBridge-computedFHWA discontinued this calculated item; it does not determine current condition, funding eligibility, posting, or closure. How the historical reference is calculated.
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Structural Details
- Year Built
- 1979
- Material
- Steel Continuous
- Number of Spans
- 15
- Structure Length
- 1283.2 m (4210 ft)
- Deck Width
- 12.0 m (39 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 12,000 vehicles/day
- Structure Number
- 000000000007425
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) rates fair at 6/9, minor deterioration that routine maintenance should address.
- • The superstructure (beams and supports above the deck) is in fair condition (6/9), with minor deterioration that may require routine maintenance.
- • The substructure (piers and abutments) is in poor condition (4/9), showing advanced deterioration that may require priority repair.
How to read this record
US 21 SB is in the federal Poor condition category. That is a component-based result, not a closure order.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Understand what Poor condition does and does not mean before drawing conclusions. Poor condition explained
- Compare US 21 SB against other structures in Beaufort and across South Carolina. South Carolina bridges
- Noticed visible damage or a safety concern? Report it to the agency that owns the bridge, or call 911 in an emergency. How to report a bridge
Condition codes come straight from the FHWA National Bridge Inventory and are not a real-time safety judgment. Only the owning agency, a state DOT, county, or other owner, can post, restrict, or close a bridge.
Frequently Asked Questions
What do the condition ratings mean for US 21 SB?
US 21 SB in Beaufort, South Carolina has a deck rating of 6/9, superstructure rating of 6/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is US 21 SB inspected?
US 21 SB's responsible agency sets its routine interval under FHWA's risk-based inspection rules; this page does not expose the scheduled interval. It carries about 12,000 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. US 21 SB is currently shown as Poor condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for US 21 SB?
US 21 SB has an NBI inventory load rating of 13.9 metric tons.
Who is responsible for maintaining US 21 SB?
US 21 SB is owned and maintained by State Highway Agency.
How old is US 21 SB and does age affect safety?
US 21 SB was built in 1979, making it 47 years old.
Disclaimer: Bridge condition data is from the FHWA NBI and reflects the last reported inspection. A Poor condition rating is not a live declaration that a bridge is closed or unsafe for travel. For current closure, posting, or safety information, contact the responsible transportation agency.
Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.