Nfa 1921 (sa 9420) over South Harpeth River
GoodWilliamson County, Tennessee · 3.6 MI NE JCT SR96&SR100 · Structure no. 94019210003
- Built
- 1985
- 40 years old
- Condition
- Good
- inspected June 2023
- Type
- Box Beam or Girders - Single or Spread
- Prestressed Concrete Continuous
- Length
- 184 ft
- 3 main spans
- Daily traffic
- 703
- 2021 count
- Owner
- County
- County Highway Agency
About this bridge
Nfa 1921 (sa 9420) over South Harpeth River is a prestressed concrete continuous box beam or girders - single or spread carrying Nfa 1921 (sa 9420) over South Harpeth River in Williamson County, Tennessee. It was built in 1985, so it is 40 years old, younger than the Tennessee average of 47.4 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 703 vehicles a day, roughly 3% of them trucks, projected to reach 942 by 2042. The structure is 184 ft (56.1 m) long and 30 ft wide. If it were closed, the detour would be 123.7 mi (199 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Nfa 1921 (sa 9420) over South Harpeth River built?
It was built in 1985, making it 40 years old in 2025.
What condition is Nfa 1921 (sa 9420) over South Harpeth 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 June 2023.
How much traffic does Nfa 1921 (sa 9420) over South Harpeth River carry?
About 703 vehicles per day (2021 count), of which roughly 3% are trucks.
How long is Nfa 1921 (sa 9420) over South Harpeth River?
The structure is 184 ft (56.1 m) long with a longest span of 62 ft (18.9 m) and a deck 30 ft wide.
Who owns Nfa 1921 (sa 9420) over South Harpeth River?
It is owned by the County Highway Agency.