US Bridges

I181 over Knob Creek

Fair

Washington County, Tennessee · East of Johnson City · Structure no. 90I00260065

Built
1969
56 years old, rebuilt 2000
Condition
Fair
inspected September 2023
Type
Culvert
Concrete Continuous
Length
33 ft
3 main spans
Daily traffic
60,503
2021 count
Owner
State
State Highway Agency

About this bridge

I181 over Knob Creek is a concrete continuous culvert carrying I181 over Knob Creek in Washington County, Tennessee. It was built in 1969 and reconstructed in 2000, so it is 56 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 60,503 vehicles a day, roughly 6% of them trucks, projected to reach 72,664 by 2042. The structure is 33 ft (10.1 m) long. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesI181
CrossesKnob Creek
LocationEast of Johnson City
RouteInterstate 26
CountyWashington County
StateTennessee
Coordinates36.35493, -82.39784
Functional classUrban Principal Arterial - Interstate

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 protection7 GoodSome minor problems.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionSeptember 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
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.5 US tons
Inventory rating35.7 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans3
Design loadHS 20
Structure length33 ft (10.1 m)
Longest span10 ft (3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic60,503 (2021)
Projected traffic72,664 by 2042
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$341,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I181 over Knob Creek built?

It was built in 1969, making it 56 years old in 2025. It was reconstructed in 2000.

What condition is I181 over Knob 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 September 2023.

How much traffic does I181 over Knob Creek carry?

About 60,503 vehicles per day (2021 count), of which roughly 6% are trucks.

How long is I181 over Knob Creek?

The structure is 33 ft (10.1 m) long with a longest span of 10 ft (3 m).

Who owns I181 over Knob Creek?

It is owned by the State Highway Agency.