US Bridges

Nfa 4748 (sa 9423) over Overflow W. Harpeth Riv.

Fair

Williamson County, Tennessee · 2.2 MI NE JCT SR46&SR96 · Structure no. 94047480001

Built
1999
26 years old
Condition
Fair
inspected July 2023
Type
Box Beam or Girders - Single or Spread
Prestressed Concrete
Length
74 ft
1 main span
Daily traffic
2,592
2021 count
Owner
County
County Highway Agency

About this bridge

Nfa 4748 (sa 9423) over Overflow W. Harpeth Riv. is a prestressed concrete box beam or girders - single or spread carrying Nfa 4748 (sa 9423) over Overflow W. Harpeth Riv. in Williamson County, Tennessee. It was built in 1999, so it is 26 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 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 74 ft (22.7 m) long and 27 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

Open in Google Maps
CarriesNfa 4748 (sa 9423)
CrossesOverflow W. Harpeth Riv.
Location2.2 MI NE JCT SR46&SR96
RouteCounty Highway 4748
CountyWilliamson County
StateTennessee
Coordinates35.96603, -86.9192
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
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
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 rating59.5 US tons
Inventory rating35.7 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length74 ft (22.7 m)
Longest span73 ft (22.4 m)
Deck width27 ft (8.3 m)
Roadway width26 ft (7.9 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 closed8.7 mi (14 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Nfa 4748 (sa 9423) over Overflow W. Harpeth Riv. built?

It was built in 1999, making it 26 years old in 2025.

What condition is Nfa 4748 (sa 9423) over Overflow W. Harpeth Riv. 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 9423) over Overflow W. Harpeth Riv. carry?

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

How long is Nfa 4748 (sa 9423) over Overflow W. Harpeth Riv.?

The structure is 74 ft (22.7 m) long with a longest span of 73 ft (22.4 m) and a deck 27 ft wide.

Who owns Nfa 4748 (sa 9423) over Overflow W. Harpeth Riv.?

It is owned by the County Highway Agency.