US Bridges

Seneca Hollow 636 over Rte. I-81

Good

Montgomery County, Virginia · 0.75-RT 821;2.0-RT 11&460 · Structure no. 000000000029536

Built
2012
13 years old
Condition
Good
inspected April 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
217 ft
2 main spans
Daily traffic
260
2022 count
Owner
State
State Highway Agency

About this bridge

Seneca Hollow 636 over Rte. I-81 is a prestressed concrete continuous stringer/multi-beam or girder carrying Seneca Hollow 636 over Rte. I-81 in Montgomery County, Virginia. It was built in 2012, so it is 13 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 260 vehicles a day, projected to reach 293 by 2045. The structure is 217 ft (66.2 m) long and 29 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesSeneca Hollow 636
CrossesRte. I-81
Location0.75-RT 821;2.0-RT 11&460
RouteCounty Highway 636
CountyMontgomery County
StateVirginia
Coordinates37.19614, -80.26984
Functional classRural Minor Collector

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.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating83 US tons
Inventory rating64 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHL 93
Structure length217 ft (66.2 m)
Longest span109 ft (33.1 m)
Deck width29 ft (8.9 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic260 (2022)
Projected traffic293 by 2045
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

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 Seneca Hollow 636 over Rte. I-81 built?

It was built in 2012, making it 13 years old in 2025.

What condition is Seneca Hollow 636 over Rte. I-81 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 April 2023.

How much traffic does Seneca Hollow 636 over Rte. I-81 carry?

About 260 vehicles per day (2022 count).

How long is Seneca Hollow 636 over Rte. I-81?

The structure is 217 ft (66.2 m) long with a longest span of 109 ft (33.1 m) and a deck 29 ft wide.

Who owns Seneca Hollow 636 over Rte. I-81?

It is owned by the State Highway Agency.