US Bridges

S-20-420 over Unnamed Stream

Fair

Fairfield County, South Carolina · 11.5MI SW Winnsboro · Structure no. 000000000005519

Built
1969
56 years old
Condition
Fair
inspected April 2024
Type
Slab
Concrete
Length
60 ft
4 main spans
Daily traffic
125
2023 count
Owner
State
State Highway Agency

About this bridge

S-20-420 over Unnamed Stream is a concrete slab carrying S-20-420 over Unnamed Stream in Fairfield County, South Carolina. It was built in 1969, so it is 56 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 125 vehicles a day, roughly 5% of them trucks, projected to reach 160 by 2043. The structure is 60 ft (18.3 m) long and 28 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesS-20-420
CrossesUnnamed Stream
Location11.5MI SW Winnsboro
RouteState Highway 420
CountyFairfield County
StateSouth Carolina
Coordinates34.23417, -81.18056
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 protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating28.5 US tons
Inventory rating17.2 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, precast panels
Main spans4
Design loadH 10
Structure length60 ft (18.3 m)
Longest span15 ft (4.6 m)
Deck width28 ft (8.4 m)
Roadway width26 ft (8 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 closed3.1 mi (5 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 proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$92,000 (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was S-20-420 over Unnamed Stream built?

It was built in 1969, making it 56 years old in 2025.

What condition is S-20-420 over Unnamed Stream 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 2024.

How much traffic does S-20-420 over Unnamed Stream carry?

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

How long is S-20-420 over Unnamed Stream?

The structure is 60 ft (18.3 m) long with a longest span of 15 ft (4.6 m) and a deck 28 ft wide.

Who owns S-20-420 over Unnamed Stream?

It is owned by the State Highway Agency.