US Bridges

I-77 Nbl over I-20 & I-20 Ramp

Good

Richland County, South Carolina · 9 MI E Columbia · Structure no. 000000000007930

Built
1985
40 years old, rebuilt 2018
Condition
Good
inspected January 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
370 ft
5 main spans
Daily traffic
47,200
2023 count
Owner
State
State Highway Agency

About this bridge

I-77 Nbl over I-20 & I-20 Ramp is a steel continuous stringer/multi-beam or girder carrying I-77 Nbl over I-20 & I-20 Ramp in Richland County, South Carolina. It was built in 1985 and reconstructed in 2018, 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 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 47,200 vehicles a day, roughly 16% of them trucks, projected to reach 58,528 by 2043. The structure is 370 ft (112.7 m) long and 63 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesI-77 Nbl
CrossesI-20 & I-20 Ramp
Location9 MI E Columbia
RouteInterstate 77
Coordinates34.06771, -80.92212
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.
Last inspectionJanuary 2024
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 geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating28.2 US tons
Inventory rating21.8 US tons

Structure

MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20 + Mod
Structure length370 ft (112.7 m)
Longest span92 ft (28 m)
Deck width63 ft (19.1 m)
Roadway width59 ft (18.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic47,200 (2023)
Projected traffic58,528 by 2043
Trucks16%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkNon-Interstate 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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-77 Nbl over I-20 & I-20 Ramp built?

It was built in 1985, making it 40 years old in 2025. It was reconstructed in 2018.

What condition is I-77 Nbl over I-20 & I-20 Ramp 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 January 2024.

How much traffic does I-77 Nbl over I-20 & I-20 Ramp carry?

About 47,200 vehicles per day (2023 count), of which roughly 16% are trucks.

How long is I-77 Nbl over I-20 & I-20 Ramp?

The structure is 370 ft (112.7 m) long with a longest span of 92 ft (28 m) and a deck 63 ft wide.

Who owns I-77 Nbl over I-20 & I-20 Ramp?

It is owned by the State Highway Agency.