US 521 NB
Carrying US 521 NB over TWELVE MILE CREEK
12.0 MI N LANCASTER, Lancaster, South Carolina
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: US 521 NB
The US 521 NB bridge in Lancaster, South Carolina carries US 521 NB over TWELVE MILE CREEK. It was built in 1977, making it 49 years old today. The structure is built primarily of prestressed concrete and spans 2 sections, stretching 86.6 meters (284 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 7/9, substructure at 6/9. The weakest component sits in fair condition. None of this bridge's reported major components fall into the Poor condition range. Its NBI inventory load rating is 27.9 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How US 521 NB 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 How the historical reference is calculated.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
- 1977
- Material
- Prestressed Concrete
- Number of Spans
- 2
- Structure Length
- 86.6 m (284 ft)
- Deck Width
- 13.1 m (43 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 10,250 vehicles/day
- Structure Number
- 000000000006997
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) is in fair condition (6/9), with minor deterioration that may require routine maintenance.
- • The superstructure (beams and supports above the deck) rates good at 7/9, with no significant deterioration on file.
- • The substructure (piers and abutments) rates fair at 6/9, minor deterioration that routine maintenance should address.
How to read this record
This page shows what the last federal inspection recorded, not whether US 521 NB is safe to cross today. Here is how to use it.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Learn how the 0–9 condition scale and Good/Fair/Poor categories are defined. How condition ratings work
- Compare US 521 NB 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 NB?
US 521 NB in Lancaster, South Carolina has a deck rating of 6/9, superstructure rating of 7/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is US 521 NB inspected?
US 521 NB'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 NB is currently shown as Fair condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for US 521 NB?
US 521 NB has an NBI inventory load rating of 27.9 metric tons.
Who is responsible for maintaining US 521 NB?
US 521 NB is owned and maintained by State Highway Agency.
How old is US 521 NB and does age affect safety?
US 521 NB was built in 1977, making it 49 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.