US Bridges

Nfa 870 (sa 5705) over Cobb Creek

Fair

Madison County, Tennessee · 3.7 MI NW JCT SR18&HARDEM · Structure no. 57F00060001

Built
1968
57 years old, rebuilt 2017
Condition
Fair
inspected May 2023
Type
Channel Beam
Concrete
Length
57 ft
3 main spans
Daily traffic
280
2021 count
Owner
County
County Highway Agency

About this bridge

Nfa 870 (sa 5705) over Cobb Creek is a concrete channel beam carrying Nfa 870 (sa 5705) over Cobb Creek in Madison County, Tennessee. It was built in 1968 and reconstructed in 2017, so it is 57 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 280 vehicles a day, roughly 3% of them trucks, projected to reach 544 by 2041. The structure is 57 ft (17.4 m) long and 27 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesNfa 870 (sa 5705)
CrossesCobb Creek
Location3.7 MI NW JCT SR18&HARDEM
RouteCounty Highway 870
CountyMadison County
StateTennessee
Coordinates35.47086, -88.91881
Functional classRural Minor 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure8 Very GoodNo problems noted.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating37.1 US tons
Inventory rating28.5 US tons

Structure

Structure typeChannel Beam
MaterialConcrete
DeckConcrete, precast panels
Main spans3
Design loadHS 15
Structure length57 ft (17.4 m)
Longest span19 ft (5.8 m)
Deck width27 ft (8.1 m)
Roadway width26 ft (7.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic280 (2021)
Projected traffic544 by 2041
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$133,000 (2021 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Nfa 870 (sa 5705) over Cobb Creek built?

It was built in 1968, making it 57 years old in 2025. It was reconstructed in 2017.

What condition is Nfa 870 (sa 5705) over Cobb Creek 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 870 (sa 5705) over Cobb Creek carry?

About 280 vehicles per day (2021 count), of which roughly 3% are trucks.

How long is Nfa 870 (sa 5705) over Cobb Creek?

The structure is 57 ft (17.4 m) long with a longest span of 19 ft (5.8 m) and a deck 27 ft wide.

Who owns Nfa 870 (sa 5705) over Cobb Creek?

It is owned by the County Highway Agency.