US Bridges

S-21-38 over Lake Swamp

Fair

Florence County, South Carolina · 4 MI W Effingham · Structure no. 000000000007561

Built
1982
43 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
180 ft
6 main spans
Daily traffic
425
2023 count
Owner
State
State Highway Agency

About this bridge

S-21-38 over Lake Swamp is a prestressed concrete stringer/multi-beam or girder carrying S-21-38 over Lake Swamp in Florence County, South Carolina. It was built in 1982, so it is 43 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 425 vehicles a day, roughly 7% of them trucks, projected to reach 591 by 2043. The structure is 180 ft (54.9 m) long and 33 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesS-21-38
CrossesLake Swamp
Location4 MI W Effingham
RouteState Highway 38
CountyFlorence County
StateSouth Carolina
Coordinates34.02833, -79.84193
Functional classRural Minor Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44 US tons
Inventory rating21.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans6
Design loadH 15
Structure length180 ft (54.9 m)
Longest span30 ft (9.1 m)
Deck width33 ft (10.2 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic425 (2023)
Projected traffic591 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 statusHistorical significance not determinable at this time
Work proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$273,000 (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was S-21-38 over Lake Swamp built?

It was built in 1982, making it 43 years old in 2025.

What condition is S-21-38 over Lake 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-21-38 over Lake Swamp carry?

About 425 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is S-21-38 over Lake Swamp?

The structure is 180 ft (54.9 m) long with a longest span of 30 ft (9.1 m) and a deck 33 ft wide.

Who owns S-21-38 over Lake Swamp?

It is owned by the State Highway Agency.