US Bridges

S-578/WESTBURY RD over Trib to Polk Swamp

Fair

Dorchester County, South Carolina · 3.7 MI SW ST George · Structure no. 000000000005712

Built
1970
55 years old
Condition
Fair
inspected May 2023
Type
Slab
Concrete
Length
45 ft
3 main spans
Daily traffic
225
2023 count
Owner
State
State Highway Agency

About this bridge

S-578/WESTBURY RD over Trib to Polk Swamp is a concrete slab carrying S-578/WESTBURY RD over Trib to Polk Swamp in Dorchester County, South Carolina. It was built in 1970, so it is 55 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 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 225 vehicles a day, roughly 5% of them trucks, projected to reach 288 by 2043. The structure is 45 ft (13.7 m) long and 33 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesS-578/WESTBURY RD
CrossesTrib to Polk Swamp
Location3.7 MI SW ST George
RouteState Highway 578
CountyDorchester County
StateSouth Carolina
Coordinates33.14452, -80.60536
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.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2023
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 geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating34.3 US tons
Inventory rating20.4 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, precast panels
Main spans3
Design loadH 10
Structure length45 ft (13.7 m)
Longest span15 ft (4.6 m)
Deck width33 ft (10.1 m)
Roadway width31 ft (9.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic225 (2023)
Projected traffic288 by 2043
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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-578/WESTBURY RD over Trib to Polk Swamp built?

It was built in 1970, making it 55 years old in 2025.

What condition is S-578/WESTBURY RD over Trib to Polk 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 May 2023.

How much traffic does S-578/WESTBURY RD over Trib to Polk Swamp carry?

About 225 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is S-578/WESTBURY RD over Trib to Polk Swamp?

The structure is 45 ft (13.7 m) long with a longest span of 15 ft (4.6 m) and a deck 33 ft wide.

Who owns S-578/WESTBURY RD over Trib to Polk Swamp?

It is owned by the State Highway Agency.