US Bridges

I-77 NB over Congaree Swamp

Good

Richland County, South Carolina · 5 MI S of Columbia · Structure no. 000000000007826

Built
1984
41 years old
Condition
Good
inspected November 2023
Type
Slab
Concrete Continuous
Length
1,320 ft
44 main spans
Daily traffic
47,350
2023 count
Owner
State
State Highway Agency

About this bridge

I-77 NB over Congaree Swamp is a concrete continuous slab carrying I-77 NB over Congaree Swamp in Richland County, South Carolina. It was built in 1984, so it is 41 years old, younger than the South Carolina average of 48 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 47,350 vehicles a day, roughly 16% of them trucks, projected to reach 58,714 by 2043. The structure is 1,320 ft (402.3 m) long and 59 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-77 NB
CrossesCongaree Swamp
Location5 MI S of Columbia
RouteInterstate 77
CountyRichland County
StateSouth Carolina
Coordinates33.94071, -81.0041
Functional classUrban Principal Arterial - Interstate

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.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating53.2 US tons
Inventory rating41.1 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans44
Design loadHS 20 + Mod
Structure length1,320 ft (402.3 m)
Longest span30 ft (9.1 m)
Deck width59 ft (18.1 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic47,350 (2023)
Projected traffic58,714 by 2043
Trucks16%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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 I-77 NB over Congaree Swamp built?

It was built in 1984, making it 41 years old in 2025.

What condition is I-77 NB over Congaree Swamp 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 November 2023.

How much traffic does I-77 NB over Congaree Swamp carry?

About 47,350 vehicles per day (2023 count), of which roughly 16% are trucks.

How long is I-77 NB over Congaree Swamp?

The structure is 1,320 ft (402.3 m) long with a longest span of 30 ft (9.1 m) and a deck 59 ft wide.

Who owns I-77 NB over Congaree Swamp?

It is owned by the State Highway Agency.