US Bridges

S-21-55 over Sparrow Swamp

Fair

Florence County, South Carolina · 5MI NW of Effingham · Structure no. 000000000008350

Built
1990
35 years old
Condition
Fair
inspected April 2023
Type
Slab
Concrete
Length
120 ft
8 main spans
Daily traffic
950
2023 count
Owner
State
State Highway Agency

About this bridge

S-21-55 over Sparrow Swamp is a concrete slab carrying S-21-55 over Sparrow Swamp in Florence County, South Carolina. It was built in 1990, so it is 35 years old, younger 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 6 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 950 vehicles a day, roughly 7% of them trucks, projected to reach 1,216 by 2043. The structure is 120 ft (36.6 m) long and 38 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesS-21-55
CrossesSparrow Swamp
Location5MI NW of Effingham
RouteState Highway 55
CountyFlorence County
StateSouth Carolina
Coordinates34.02936, -79.81599
Functional classRural Local

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating54.7 US tons
Inventory rating42.1 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, precast panels
Main spans8
Design loadHS 20
Structure length120 ft (36.6 m)
Longest span15 ft (4.6 m)
Deck width38 ft (11.7 m)
Roadway width34 ft (10.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic950 (2023)
Projected traffic1,216 by 2043
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was S-21-55 over Sparrow Swamp built?

It was built in 1990, making it 35 years old in 2025.

What condition is S-21-55 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 April 2023.

How much traffic does S-21-55 over Sparrow Swamp carry?

About 950 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is S-21-55 over Sparrow Swamp?

The structure is 120 ft (36.6 m) long with a longest span of 15 ft (4.6 m) and a deck 38 ft wide.

Who owns S-21-55 over Sparrow Swamp?

It is owned by the State Highway Agency.