US Bridges

I-81 Nbl & Sbl over RTE 11 NSRR Mfh River

Good

Smyth County, Virginia · 5.21TO R11 & 1.84 to R683 · Structure no. 000000000031136

Built
2021
4 years old
Condition
Good
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
410 ft
3 main spans
Daily traffic
31,084
2022 count
Owner
State
State Highway Agency

About this bridge

I-81 Nbl & Sbl over RTE 11 NSRR Mfh River is a steel continuous stringer/multi-beam or girder carrying I-81 Nbl & Sbl over RTE 11 NSRR Mfh River in Smyth County, Virginia. It was built in 2021, so it is 4 years old, younger than the Virginia average of 50.7 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 31,084 vehicles a day, roughly 1% of them trucks, projected to reach 34,659 by 2045. The structure is 410 ft (125 m) long and 89 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesI-81 Nbl & Sbl
CrossesRTE 11 NSRR Mfh River
Location5.21TO R11 & 1.84 to R683
RouteInterstate 81
Coordinates36.8743, -81.39883
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.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 22 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating74 US tons
Inventory rating57 US tons

Structure

MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length410 ft (125 m)
Longest span141 ft (42.9 m)
Deck width89 ft (27.2 m)
Roadway width42 ft (12.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic31,084 (2022)
Projected traffic34,659 by 2045
Trucks1%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway, waterway and railroad
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was I-81 Nbl & Sbl over RTE 11 NSRR Mfh River built?

It was built in 2021, making it 4 years old in 2025.

What condition is I-81 Nbl & Sbl over RTE 11 NSRR Mfh River 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 July 2023.

How much traffic does I-81 Nbl & Sbl over RTE 11 NSRR Mfh River carry?

About 31,084 vehicles per day (2022 count), of which roughly 1% are trucks.

How long is I-81 Nbl & Sbl over RTE 11 NSRR Mfh River?

The structure is 410 ft (125 m) long with a longest span of 141 ft (42.9 m) and a deck 89 ft wide.

Who owns I-81 Nbl & Sbl over RTE 11 NSRR Mfh River?

It is owned by the State Highway Agency.