US 17 ALT
Carrying US 17 ALT over EDISTO RIVER
14MI S SUMRVL, Dorchester, South Carolina
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
US 17 ALT in Dorchester, South Carolina is rated Fair in the FHWA's 2024 National Bridge Inventory.
Built in 1972, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 6. The lowest applicable rating sets the federal condition category, so this Fair 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:000000000006087
INTERSTATE-ERA · STEEL · MULTI-SPAN · TIED-CTRL · HEAVY-ADT · STANDARD-LOAD · CAT-FAIR
- INTERSTATE-ERA 1950–1979
- STEEL Steel
- MULTI-SPAN 3 spans
- TIED-CTRL Tied control
- HEAVY-ADT Heavy ADT
- STANDARD-LOAD Standard load
- CAT-FAIR Fair
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 17 ALT
The US 17 ALT bridge in Dorchester, South Carolina carries US 17 ALT over EDISTO RIVER. It was built in 1972, making it 54 years old today. The structure is built primarily of steel continuous and spans 3 sections, stretching 241.1 meters (791 feet) end to end. Daily traffic averages 10,600 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 6/9. The weakest component sits in fair condition. All reported major components score above the Poor range.
How US 17 ALT compares
Age against the county: built in 1972, earlier than 96 of Dorchester's 198 bridges with a recorded construction year (48%), against a county median build year of 1972.
Live comparison across South Carolina bridges with a recorded inventory load rating (9,483 of 9,490 rated).
US 17 ALT vs every rated South Carolina bridge
Inventory load rating (metric tons), FHWA NBI, this state
30 Top 49% higher than 51% 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.
Dorchester inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 198 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
- 1972
- Material
- Steel Continuous
- Number of Spans
- 3
- Structure Length
- 241.1 m (791 ft)
- Deck Width
- 16.2 m (53 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 10,600 vehicles/day
- Structure Number
- 000000000006087
Condition Analysis
- • At 6/9, the deck (driving surface) shows fair condition, with minor wear flagged for upkeep.
- • The superstructure (beams and supports above the deck) is in fair condition (6/9), with minor deterioration that may require routine maintenance.
- • At 6/9, the substructure (piers and abutments) shows fair condition, with minor wear flagged for upkeep.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
This page shows what the last federal inspection recorded, not whether US 17 ALT 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 17 ALT against other structures in Dorchester 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 17 ALT?
US 17 ALT in Dorchester, South Carolina has a deck rating of 6/9, superstructure rating of 6/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is US 17 ALT inspected?
US 17 ALT'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 10,600 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. US 17 ALT 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 17 ALT?
US 17 ALT has an NBI inventory load rating of 29.5 metric tons.
Who is responsible for maintaining US 17 ALT?
US 17 ALT is owned and maintained by State Highway Agency.
How old is US 17 ALT and does age affect safety?
US 17 ALT was built in 1972, making it 54 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.
Share this inspection record
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.