US Bridges

I-81 Nbl over Route 689

Fair

Smyth County, Virginia · 1.04 to R11&6.01 to R683 · Structure no. 000000000017446

Built
1963
62 years old, rebuilt 1991
Condition
Fair
inspected February 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
148 ft
3 main spans
Daily traffic
14,838
2022 count
Owner
State
State Highway Agency

About this bridge

I-81 Nbl over Route 689 is a steel stringer/multi-beam or girder carrying I-81 Nbl over Route 689 in Smyth County, Virginia. It was built in 1963 and reconstructed in 1991, so it is 62 years old, older 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 5 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 14,838 vehicles a day, roughly 1% of them trucks, projected to reach 16,544 by 2042. The structure is 148 ft (45.2 m) long and 44 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesI-81 Nbl
CrossesRoute 689
Location1.04 to R11&6.01 to R683
RouteInterstate 81
CountySmyth County
StateVirginia
Coordinates36.85353, -81.46741
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionFebruary 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 geometry8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating55 US tons
Inventory rating43 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length148 ft (45.2 m)
Longest span54 ft (16.5 m)
Deck width44 ft (13.4 m)
Roadway width42 ft (12.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic14,838 (2022)
Projected traffic16,544 by 2042
Trucks1%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed9.9 mi (16 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$130 million (2019 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-81 Nbl over Route 689 built?

It was built in 1963, making it 62 years old in 2025. It was reconstructed in 1991.

What condition is I-81 Nbl over Route 689 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 February 2024.

How much traffic does I-81 Nbl over Route 689 carry?

About 14,838 vehicles per day (2022 count), of which roughly 1% are trucks.

How long is I-81 Nbl over Route 689?

The structure is 148 ft (45.2 m) long with a longest span of 54 ft (16.5 m) and a deck 44 ft wide.

Who owns I-81 Nbl over Route 689?

It is owned by the State Highway Agency.