US Bridges

South Cobb Drive over CSX Railroad (639142K)

Good

Cobb County, Georgia · 3.4 MI SE of Smyrna · Structure no. 000000006700530

Built
1976
49 years old
Condition
Good
inspected March 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
180 ft
3 main spans
Daily traffic
31,800
2024 count
Owner
State
State Highway Agency

About this bridge

South Cobb Drive over CSX Railroad (639142K) is a steel stringer/multi-beam or girder carrying South Cobb Drive over CSX Railroad (639142K) in Cobb County, Georgia. It was built in 1976, so it is 49 years old, older than the Georgia average of 47.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 31,800 vehicles a day, roughly 1% of them trucks, projected to reach 45,780 by 2032. The structure is 180 ft (54.9 m) long and 68 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesSouth Cobb Drive
CrossesCSX Railroad (639142K)
Location3.4 MI SE of Smyrna
RouteState Highway 280
CountyCobb County
StateGeorgia
Coordinates33.84002, -84.49619
Functional classUrban Other Principal Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
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
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44 US tons
Inventory rating25.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length180 ft (54.9 m)
Longest span66 ft (20.1 m)
Deck width68 ft (20.8 m)
Roadway width66 ft (20.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic31,800 (2024)
Projected traffic45,780 by 2032
Trucks1%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway
CrossesRailroad
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemYes

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was South Cobb Drive over CSX Railroad (639142K) built?

It was built in 1976, making it 49 years old in 2025.

What condition is South Cobb Drive over CSX Railroad (639142K) in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in March 2023.

How much traffic does South Cobb Drive over CSX Railroad (639142K) carry?

About 31,800 vehicles per day (2024 count), of which roughly 1% are trucks.

How long is South Cobb Drive over CSX Railroad (639142K)?

The structure is 180 ft (54.9 m) long with a longest span of 66 ft (20.1 m) and a deck 68 ft wide.

Who owns South Cobb Drive over CSX Railroad (639142K)?

It is owned by the State Highway Agency.