US Bridges

I840 over I840-RL/BOSTON Theta RD

Good

Williamson County, Tennessee · 11 MI W Jct. I65 & I840 · Structure no. 94SR8400031

Built
2001
24 years old
Condition
Good
inspected December 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
851 ft
7 main spans
Daily traffic
22,556
2021 count
Owner
State
State Highway Agency

About this bridge

I840 over I840-RL/BOSTON Theta RD is a prestressed concrete continuous stringer/multi-beam or girder carrying I840 over I840-RL/BOSTON Theta RD in Williamson County, Tennessee. It was built in 2001, so it is 24 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 22,556 vehicles a day, roughly 7% of them trucks, projected to reach 34,176 by 2041. The structure is 851 ft (259.4 m) long and 43 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

CarriesI840
CrossesI840-RL/BOSTON Theta RD
Location11 MI W Jct. I65 & I840
RouteInterstate 840
Coordinates35.819, -87.03558
Functional classRural Principal Arterial - Interstate

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating71.4 US tons
Inventory rating30.8 US tons

Structure

MaterialPrestressed Concrete Continuous
DeckConcrete, precast panels
Main spans7
Design loadHS 20
Structure length851 ft (259.4 m)
Longest span153 ft (46.5 m)
Deck width43 ft (13.2 m)
Roadway width41 ft (12.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic22,556 (2021)
Projected traffic34,176 by 2041
Trucks7%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and waterway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 I840 over I840-RL/BOSTON Theta RD built?

It was built in 2001, making it 24 years old in 2025.

What condition is I840 over I840-RL/BOSTON Theta RD 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 December 2024.

How much traffic does I840 over I840-RL/BOSTON Theta RD carry?

About 22,556 vehicles per day (2021 count), of which roughly 7% are trucks.

How long is I840 over I840-RL/BOSTON Theta RD?

The structure is 851 ft (259.4 m) long with a longest span of 153 ft (46.5 m) and a deck 43 ft wide.

Who owns I840 over I840-RL/BOSTON Theta RD?

It is owned by the State Highway Agency.