US Bridges

Nfa 4748 (sa 9427) over Harpeth River

Fair

Williamson County, Tennessee · 2.1 MI NE JCT SR46&SR96 · Structure no. 940A0710001

Built
1950
75 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
219 ft
3 main spans
Daily traffic
2,592
2021 count
Owner
County
County Highway Agency

About this bridge

Nfa 4748 (sa 9427) over Harpeth River is a prestressed concrete stringer/multi-beam or girder carrying Nfa 4748 (sa 9427) over Harpeth River in Williamson County, Tennessee. It was built in 1950, so it is 75 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 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 2,592 vehicles a day, roughly 3% of them trucks, projected to reach 2,955 by 2041. The structure is 219 ft (66.8 m) long and 29 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesNfa 4748 (sa 9427)
CrossesHarpeth River
Location2.1 MI NE JCT SR46&SR96
RouteCounty Highway 4748
CountyWilliamson County
StateTennessee
Coordinates35.9677, -86.9008
Functional classUrban 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating59.5 US tons
Inventory rating35.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckOther
Main spans3 (+2 approach)
Design loadHS 20
Structure length219 ft (66.8 m)
Longest span54 ft (16.5 m)
Deck width29 ft (8.7 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,592 (2021)
Projected traffic2,955 by 2041
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 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 4748 (sa 9427) over Harpeth River built?

It was built in 1950, making it 75 years old in 2025.

What condition is Nfa 4748 (sa 9427) over 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 July 2023.

How much traffic does Nfa 4748 (sa 9427) over Harpeth River carry?

About 2,592 vehicles per day (2021 count), of which roughly 3% are trucks.

How long is Nfa 4748 (sa 9427) over Harpeth River?

The structure is 219 ft (66.8 m) long with a longest span of 54 ft (16.5 m) and a deck 29 ft wide.

Who owns Nfa 4748 (sa 9427) over Harpeth River?

It is owned by the County Highway Agency.