US Bridges

Ramp On/Off I-77NB over US 21

Good

York County, South Carolina · 4 MI NE of Rock Hill · Structure no. 000000000009857

Built
2004
21 years old
Condition
Good
inspected March 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
201 ft
3 main spans
Daily traffic
8,300
2022 count
Owner
State
State Highway Agency

About this bridge

Ramp On/Off I-77NB over US 21 is a steel stringer/multi-beam or girder carrying Ramp On/Off I-77NB over US 21 in York County, South Carolina. It was built in 2004, so it is 21 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 8,300 vehicles a day, roughly 9% of them trucks, projected to reach 17,513 by 2042. The structure is 201 ft (61.3 m) long and 43 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesRamp On/Off I-77NB
CrossesUS 21
Location4 MI NE of Rock Hill
RouteInterstate 77
CountyYork County
StateSouth Carolina
Coordinates34.9737, -80.98646
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.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation8: Equal to present desirable criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating76.1 US tons
Inventory rating58.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 25 or greater
Structure length201 ft (61.3 m)
Longest span136 ft (41.5 m)
Deck width43 ft (13.1 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deck100 ft (30.5 m)

Traffic and service

Average daily traffic8,300 (2022)
Projected traffic17,513 by 2042
Trucks9%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Ramp On/Off I-77NB over US 21 built?

It was built in 2004, making it 21 years old in 2025.

What condition is Ramp On/Off I-77NB over US 21 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 2024.

How much traffic does Ramp On/Off I-77NB over US 21 carry?

About 8,300 vehicles per day (2022 count), of which roughly 9% are trucks.

How long is Ramp On/Off I-77NB over US 21?

The structure is 201 ft (61.3 m) long with a longest span of 136 ft (41.5 m) and a deck 43 ft wide.

Who owns Ramp On/Off I-77NB over US 21?

It is owned by the State Highway Agency.