US Bridges

US 401 over Sparrow Swamp

Fair

Darlington County, South Carolina · 2MI NE of Lamar · Structure no. 000000000000783

Built
1937
88 years old, rebuilt 1972
Condition
Fair
inspected January 2025
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
226 ft
9 main spans
Daily traffic
3,200
2023 count
Owner
State
State Highway Agency

About this bridge

US 401 over Sparrow Swamp is a steel continuous stringer/multi-beam or girder carrying US 401 over Sparrow Swamp in Darlington County, South Carolina. It was built in 1937 and reconstructed in 1972, so it is 88 years old, older than the South Carolina average of 48 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 3,200 vehicles a day, roughly 7% of them trucks. The structure is 226 ft (68.9 m) long and 48 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesUS 401
CrossesSparrow Swamp
Location2MI NE of Lamar
RouteU.S. Route 401
CountyDarlington County
StateSouth Carolina
Coordinates34.19242, -80.04176
Functional classRural Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating50.4 US tons
Inventory rating30 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans9
Design loadH 15
Structure length226 ft (68.9 m)
Longest span26 ft (7.8 m)
Deck width48 ft (14.5 m)
Roadway width34 ft (10.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,200 (2023)
Projected traffic—
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.2 million (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 401 over Sparrow Swamp built?

It was built in 1937, making it 88 years old in 2025. It was reconstructed in 1972.

What condition is US 401 over Sparrow Swamp in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in January 2025.

How much traffic does US 401 over Sparrow Swamp carry?

About 3,200 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is US 401 over Sparrow Swamp?

The structure is 226 ft (68.9 m) long with a longest span of 26 ft (7.8 m) and a deck 48 ft wide.

Who owns US 401 over Sparrow Swamp?

It is owned by the State Highway Agency.