US Bridges

Nfa 996 (sa 9409) over West Harpeth River

Fair

Williamson County, Tennessee · 2.7 MI N JCT SR106&SR247 · Structure no. 94F00360003

Built
1981
44 years old
Condition
Fair
inspected April 2023
Type
Culvert
Concrete
Length
31 ft
1 main span
Daily traffic
1,706
2021 count
Owner
County
County Highway Agency

About this bridge

Nfa 996 (sa 9409) over West Harpeth River is a concrete culvert carrying Nfa 996 (sa 9409) over West Harpeth River in Williamson County, Tennessee. It was built in 1981, so it is 44 years old, younger than the Tennessee average of 47.4 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 1,706 vehicles a day, roughly 3% of them trucks, projected to reach 3,296 by 2041. The structure is 31 ft (9.4 m) long and 30 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesNfa 996 (sa 9409)
CrossesWest Harpeth River
Location2.7 MI N JCT SR106&SR247
RouteCounty Highway 996
CountyWilliamson County
StateTennessee
Coordinates35.78688, -86.83382
Functional classRural Minor Collector

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 protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating56.4 US tons
Inventory rating33.6 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length31 ft (9.4 m)
Longest span20 ft (6.1 m)
Deck width30 ft (9 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,706 (2021)
Projected traffic3,296 by 2041
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Nfa 996 (sa 9409) over West Harpeth River built?

It was built in 1981, making it 44 years old in 2025.

What condition is Nfa 996 (sa 9409) over West Harpeth River 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 April 2023.

How much traffic does Nfa 996 (sa 9409) over West Harpeth River carry?

About 1,706 vehicles per day (2021 count), of which roughly 3% are trucks.

How long is Nfa 996 (sa 9409) over West Harpeth River?

The structure is 31 ft (9.4 m) long with a longest span of 20 ft (6.1 m) and a deck 30 ft wide.

Who owns Nfa 996 (sa 9409) over West Harpeth River?

It is owned by the County Highway Agency.