US Bridges

I-77 NB over Congaree River

Fair

Lexington County, South Carolina · 5 MI S Columbia · Structure no. 000000000007913

Built
1985
40 years old
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
1,308 ft
5 main spans
Daily traffic
47,350
2023 count
Owner
State
State Highway Agency

About this bridge

I-77 NB over Congaree River is a steel continuous stringer/multi-beam or girder carrying I-77 NB over Congaree River in Lexington County, South Carolina. It was built in 1985, so it is 40 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 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 47,350 vehicles a day, roughly 16% of them trucks, projected to reach 58,714 by 2043. The structure is 1,308 ft (398.7 m) long and 59 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-77 NB
CrossesCongaree River
Location5 MI S Columbia
RouteInterstate 77
CountyLexington County
StateSouth Carolina
Coordinates33.93213, -81.01752
Functional classUrban Principal Arterial - Interstate

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 protection7 GoodSome minor problems.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating49.6 US tons
Inventory rating38.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans5 (+6 approach)
Design loadHS 20 + Mod
Structure length1,308 ft (398.7 m)
Longest span180 ft (54.9 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 River built?

It was built in 1985, making it 40 years old in 2025.

What condition is I-77 NB over Congaree River 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 I-77 NB over Congaree River carry?

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

How long is I-77 NB over Congaree River?

The structure is 1,308 ft (398.7 m) long with a longest span of 180 ft (54.9 m) and a deck 59 ft wide.

Who owns I-77 NB over Congaree River?

It is owned by the State Highway Agency.