US Bridges

I-77 Sbl over I-81

Fair

Wythe County, Virginia · 0.0 to Rt 81-8.11CARROL C · Structure no. 000000000019576

Built
1978
47 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
257 ft
4 main spans
Daily traffic
4,597
2022 count
Owner
State
State Highway Agency

About this bridge

I-77 Sbl over I-81 is a steel stringer/multi-beam or girder carrying I-77 Sbl over I-81 in Wythe County, Virginia. It was built in 1978, so it is 47 years old, younger than the Virginia average of 50.7 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 4,597 vehicles a day, roughly 1% of them trucks, projected to reach 6,713 by 2045. The structure is 257 ft (78.3 m) long and 44 ft wide.

Location

Open in Google Maps
CarriesI-77 Sbl
CrossesI-81
Location0.0 to Rt 81-8.11CARROL C
RouteInterstate 77
CountyWythe County
StateVirginia
Coordinates36.94791, -80.92122
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating63.1 US tons
Inventory rating49.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length257 ft (78.3 m)
Longest span72 ft (21.8 m)
Deck width44 ft (13.4 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,597 (2022)
Projected traffic6,713 by 2045
Trucks1%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
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 Sbl over I-81 built?

It was built in 1978, making it 47 years old in 2025.

What condition is I-77 Sbl over I-81 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 June 2023.

How much traffic does I-77 Sbl over I-81 carry?

About 4,597 vehicles per day (2022 count), of which roughly 1% are trucks.

How long is I-77 Sbl over I-81?

The structure is 257 ft (78.3 m) long with a longest span of 72 ft (21.8 m) and a deck 44 ft wide.

Who owns I-77 Sbl over I-81?

It is owned by the State Highway Agency.