US 521 SB
Carrying US 521 SB over RR CSXT
11.5 MI N OF LANCASTER, Lancaster, South Carolina
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
US 521 SB in Lancaster, South Carolina sits above 25% of rated South Carolina bridges on inventory load rating (20 t), while its 1929 build year is earlier than 85% of Lancaster's recorded-year cohort (181 bridges).
US 521 SB in Lancaster, South Carolina is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1929, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 3. The lowest applicable rating sets the federal condition category, so this Poor result describes the weakest reported component rather than the structure as a whole. No NBI category is a closure decision or a live crossing-safety verdict.
NBI record plate
Structure SC:000000000000039
PRE-1950 · CONCRETE · LONG-SPAN-RUN · TIED-CTRL · HEAVY-ADT · STANDARD-LOAD · CAT-POOR
- PRE-1950 Pre-1950
- CONCRETE Concrete
- LONG-SPAN-RUN 4 spans
- TIED-CTRL Tied control
- HEAVY-ADT Heavy ADT
- STANDARD-LOAD Standard load
- CAT-POOR Poor
Inspection-sheet codes from this record’s year, material family, spans, controlling component, ADT, inventory load, and NBI category, not a live closure verdict.
Bridge Snapshot: US 521 SB
The US 521 SB bridge in Lancaster, South Carolina carries US 521 SB over RR CSXT. It was built in 1929, making it 97 years old today. It was last reconstructed in 1962, extending its service life. The structure is built primarily of concrete and spans 4 sections, stretching 39.0 meters (128 feet) end to end. Daily traffic averages 10,250 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 3/9, substructure at 3/9. The weakest component sits in poor condition. Because at least one major component scores 4 or lower, this bridge falls in FHWA's Poor condition category. That category is not a closure order.
How US 521 SB compares
Age against the county: built in 1929, earlier than 153 of Lancaster's 181 bridges with a recorded construction year (85%), against a county median build year of 1967. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across South Carolina bridges with a recorded inventory load rating (9,483 of 9,490 rated).
US 521 SB vs every rated South Carolina bridge
Inventory load rating (metric tons), FHWA NBI, this state
20 Top 75% higher than 25% of 9,483 bridges
rated South Carolina bridges, bucketed by value
Each bar is a band; taller bars hold more bridges. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source FHWA National Bridge Inventory · August 2026
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Reported 0–9 component ratings from the FHWA NBI. The highlighted component is the lowest reported input to this record’s current condition category; it is not a closure or live crossing-safety decision.
Lancaster inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 181 bridges in this county. Orthogonal to this structure's component profile above: a county catalog share, not a live crossing-safety verdict.
Structural Details
- Year Built
- 1929
- Last Reconstructed
- 1962
- Material
- Concrete
- Number of Spans
- 4
- Structure Length
- 39.0 m (128 ft)
- Deck Width
- 12.3 m (40 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 10,250 vehicles/day
- Structure Number
- 000000000000039
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) rates poor at 3/9, with advanced deterioration recorded on the latest inspection.
- • The substructure (piers and abutments) rates poor at 3/9, with advanced deterioration recorded on the latest inspection.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
US 521 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 521 SB against other structures in Lancaster 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 521 SB?
US 521 SB in Lancaster, South Carolina has a deck rating of 6/9, superstructure rating of 3/9, and substructure rating of 3/9 on the FHWA's 0–9 scale.
How often is US 521 SB inspected?
US 521 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 10,250 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. US 521 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 521 SB?
US 521 SB has an NBI inventory load rating of 20.1 metric tons.
Who is responsible for maintaining US 521 SB?
US 521 SB is owned and maintained by State Highway Agency.
How old is US 521 SB and does age affect safety?
US 521 SB was built in 1929, making it 97 years old and last reconstructed in 1962.
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.
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Send this source-bounded record or download its data card. An NBI condition category is not a closure or live crossing-safety verdict.
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Component ratings, ADT, and condition category on this page are copied from the NBI record for this structure; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.