US Bridges

I-77 Nbl over US421

Fair

Yadkin County, North Carolina · 5.3 Mi. S. Jct. US21 · Structure no. 000000001970049

Built
1974
51 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
236 ft
4 main spans
Daily traffic
13,750
2021 count
Owner
State
State Highway Agency

About this bridge

I-77 Nbl over US421 is a steel stringer/multi-beam or girder carrying I-77 Nbl over US421 in Yadkin County, North Carolina. It was built in 1974, so it is 51 years old, older than the North Carolina average of 38.7 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 13,750 vehicles a day, roughly 23% of them trucks, projected to reach 27,500 by 2040. The structure is 236 ft (71.9 m) long and 50 ft wide.

Location

Open in Google Maps
CarriesI-77 Nbl
CrossesUS421
Location5.3 Mi. S. Jct. US21
RouteInterstate 77
CountyYadkin County
StateNorth Carolina
Coordinates36.12189, -80.81373
Functional classRural 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.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating76.9 US tons
Inventory rating46 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length236 ft (71.9 m)
Longest span89 ft (27.1 m)
Deck width50 ft (15.2 m)
Roadway width47 ft (14.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,750 (2021)
Projected traffic27,500 by 2040
Trucks23%
Lanes on structure3
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed—
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 I-77 Nbl over US421 built?

It was built in 1974, making it 51 years old in 2025.

What condition is I-77 Nbl over US421 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 July 2023.

How much traffic does I-77 Nbl over US421 carry?

About 13,750 vehicles per day (2021 count), of which roughly 23% are trucks.

How long is I-77 Nbl over US421?

The structure is 236 ft (71.9 m) long with a longest span of 89 ft (27.1 m) and a deck 50 ft wide.

Who owns I-77 Nbl over US421?

It is owned by the State Highway Agency.