US Bridges

CO Rt 20 over Unknown

Fair

Jackson County, Alabama · 2.4 MI E JCT SR 65 · Structure no. 001099

Built
1934
91 years old
Condition
Fair
inspected December 2023
Type
Slab
Concrete
Length
30 ft
2 main spans
Daily traffic
42
1989 count
Owner
County
County Highway Agency

About this bridge

CO Rt 20 over Unknown is a concrete slab carrying CO Rt 20 over Unknown in Jackson County, Alabama. It was built in 1934, so it is 91 years old, older than the Alabama average of 51.1 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 42 vehicles a day, roughly 1% of them trucks, projected to reach 101 by 2039. The structure is 30 ft (9.1 m) long and 30 ft wide. If it were closed, the detour would be 98.2 mi (158 km).

Location

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CarriesCO Rt 20
CrossesUnknown
Location2.4 MI E JCT SR 65
RouteCounty Highway 20
CountyJackson County
StateAlabama
Coordinates34.75984, -86.20489
Functional classRural Local

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating36 US tons
Inventory rating26 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans2
Design loadH 10
Structure length30 ft (9.1 m)
Longest span15 ft (4.6 m)
Deck width30 ft (9.1 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic42 (1989)
Projected traffic101 by 2039
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.2 mi (158 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 proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$358,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was CO Rt 20 over Unknown built?

It was built in 1934, making it 91 years old in 2025.

What condition is CO Rt 20 over Unknown 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 December 2023.

How much traffic does CO Rt 20 over Unknown carry?

About 42 vehicles per day (1989 count), of which roughly 1% are trucks.

How long is CO Rt 20 over Unknown?

The structure is 30 ft (9.1 m) long with a longest span of 15 ft (4.6 m) and a deck 30 ft wide.

Who owns CO Rt 20 over Unknown?

It is owned by the County Highway Agency.