US Bridges

FAU 3957 over Knob CR

Fair

Washington County, Tennessee · SW of Johnson City Limits · Structure no. 90039570001

Built
1988
37 years old
Condition
Fair
inspected June 2024
Type
Culvert
Concrete Continuous
Length
27 ft
2 main spans
Daily traffic
8,214
2021 count
Owner
City
City or Municipal Highway Agency

About this bridge

FAU 3957 over Knob CR is a concrete continuous culvert carrying FAU 3957 over Knob CR in Washington County, Tennessee. It was built in 1988, so it is 37 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 6 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 8,214 vehicles a day, roughly 4% of them trucks, projected to reach 13,142 by 2042. The structure is 27 ft (8.1 m) long and 28 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesFAU 3957
CrossesKnob CR
LocationSW of Johnson City Limits
RouteCounty Highway 3957
CountyWashington County
StateTennessee
Coordinates36.34088, -82.41055
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
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating75.4 US tons
Inventory rating35.7 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length27 ft (8.1 m)
Longest span13 ft (3.9 m)
Deck width28 ft (8.4 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,214 (2021)
Projected traffic13,142 by 2042
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$194,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was FAU 3957 over Knob CR built?

It was built in 1988, making it 37 years old in 2025.

What condition is FAU 3957 over Knob CR 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 June 2024.

How much traffic does FAU 3957 over Knob CR carry?

About 8,214 vehicles per day (2021 count), of which roughly 4% are trucks.

How long is FAU 3957 over Knob CR?

The structure is 27 ft (8.1 m) long with a longest span of 13 ft (3.9 m) and a deck 28 ft wide.

Who owns FAU 3957 over Knob CR?

It is owned by the City or Municipal Highway Agency.