US Bridges

C-21-438 over Lake Swamp

FairPosted for load

Florence County, South Carolina · 1.0 MI E Timmonsville · Structure no. 000000000008742

Built
1994
31 years old
Condition
Fair
inspected November 2023
Type
Slab
Concrete
Length
90 ft
6 main spans
Daily traffic
125
2023 count
Owner
County
County Highway Agency

About this bridge

C-21-438 over Lake Swamp is a concrete slab carrying C-21-438 over Lake Swamp in Florence County, South Carolina. It was built in 1994, so it is 31 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 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 125 vehicles a day, roughly 5% of them trucks, projected to reach 160 by 2043. The structure is 90 ft (27.4 m) long and 28 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesC-21-438
CrossesLake Swamp
Location1.0 MI E Timmonsville
RouteCounty Highway 438
CountyFlorence County
StateSouth Carolina
Coordinates34.12947, -79.91566
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusPosted for load 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 adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating33.6 US tons
Inventory rating20 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, precast panels
Main spans6
Design loadH 10
Structure length90 ft (27.4 m)
Longest span15 ft (4.6 m)
Deck width28 ft (8.4 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic125 (2023)
Projected traffic160 by 2043
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 C-21-438 over Lake Swamp built?

It was built in 1994, making it 31 years old in 2025.

What condition is C-21-438 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 November 2023.

How much traffic does C-21-438 over Lake Swamp carry?

About 125 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is C-21-438 over Lake Swamp?

The structure is 90 ft (27.4 m) long with a longest span of 15 ft (4.6 m) and a deck 28 ft wide.

Who owns C-21-438 over Lake Swamp?

It is owned by the County Highway Agency.