US Bridges

Nfa A306 over West Harpeth River

Fair

Williamson County, Tennessee · 2.5 MI SE JCT SR6&SR248 · Structure no. 940A3060001

Built
1975
50 years old
Condition
Fair
inspected May 2023
Type
Culvert
Concrete Continuous
Length
48 ft
3 main spans
Daily traffic
2,130
2020 count
Owner
City
City or Municipal Highway Agency

About this bridge

Nfa A306 over West Harpeth River is a concrete continuous culvert carrying Nfa A306 over West Harpeth River in Williamson County, Tennessee. It was built in 1975, so it is 50 years old, older 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 2,130 vehicles a day, roughly 2% of them trucks, projected to reach 3,408 by 2041. The structure is 48 ft (14.6 m) long and 28 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesNfa A306
CrossesWest Harpeth River
Location2.5 MI SE JCT SR6&SR248
RouteCity Street 306
CountyWilliamson County
StateTennessee
Coordinates35.80738, -86.85245
Functional classUrban Local

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.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating75.4 US tons
Inventory rating35.7 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans3
Design loadHS 20
Structure length48 ft (14.6 m)
Longest span15 ft (4.6 m)
Deck width28 ft (8.6 m)
Roadway width26 ft (8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,130 (2020)
Projected traffic3,408 by 2041
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$241,000 (2021 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Nfa A306 over West Harpeth River built?

It was built in 1975, making it 50 years old in 2025.

What condition is Nfa A306 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 May 2023.

How much traffic does Nfa A306 over West Harpeth River carry?

About 2,130 vehicles per day (2020 count), of which roughly 2% are trucks.

How long is Nfa A306 over West Harpeth River?

The structure is 48 ft (14.6 m) long with a longest span of 15 ft (4.6 m) and a deck 28 ft wide.

Who owns Nfa A306 over West Harpeth River?

It is owned by the City or Municipal Highway Agency.