US Bridges

I-81 over Branch of Slone Branch

Fair

Pulaski County, Virginia · 3.09-RTE99; 1.28-RTE100 · Structure no. 000000000014500

Built
1965
60 years old
Condition
Fair
inspected August 2023
Type
Culvert
Concrete
Length
31 ft
3 main spans
Daily traffic
45,109
2022 count
Owner
State
State Highway Agency

About this bridge

I-81 over Branch of Slone Branch is a concrete culvert carrying I-81 over Branch of Slone Branch in Pulaski County, Virginia. It was built in 1965, so it is 60 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 45,109 vehicles a day, roughly 1% of them trucks, projected to reach 50,297 by 2045. The structure is 31 ft (9.4 m) long. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesI-81
CrossesBranch of Slone Branch
Location3.09-RTE99; 1.28-RTE100
RouteInterstate 81
CountyPulaski County
StateVirginia
Coordinates37.06611, -80.7071
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
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating99 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans3
Design loadHS 20
Structure length31 ft (9.4 m)
Longest span7 ft (2.1 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic45,109 (2022)
Projected traffic50,297 by 2045
Trucks1%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemYes

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$275.8 million (2021 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-81 over Branch of Slone Branch built?

It was built in 1965, making it 60 years old in 2025.

What condition is I-81 over Branch of Slone Branch 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 August 2023.

How much traffic does I-81 over Branch of Slone Branch carry?

About 45,109 vehicles per day (2022 count), of which roughly 1% are trucks.

How long is I-81 over Branch of Slone Branch?

The structure is 31 ft (9.4 m) long with a longest span of 7 ft (2.1 m).

Who owns I-81 over Branch of Slone Branch?

It is owned by the State Highway Agency.