US Bridges

I - 20 East over Cahaba River

Fair

Jefferson County, Alabama · I20 * Cahaba River · Structure no. 013175

Built
1984
41 years old
Condition
Fair
inspected October 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
740 ft
5 main spans
Daily traffic
35,000
2024 count
Owner
State
State Highway Agency

About this bridge

I - 20 East over Cahaba River is a steel stringer/multi-beam or girder carrying I - 20 East over Cahaba River in Jefferson County, Alabama. It was built in 1984, so it is 41 years old, younger 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 35,000 vehicles a day, roughly 21% of them trucks, projected to reach 42,286 by 2044. The structure is 740 ft (225.6 m) long and 59 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesI - 20 East
CrossesCahaba River
LocationI20 * Cahaba River
RouteInterstate 20
StateAlabama
Coordinates33.5448, -86.6184
Functional classRural 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionOctober 2024
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
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating39.9 US tons
Inventory rating23.9 US tons

Structure

MaterialSteel
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length740 ft (225.6 m)
Longest span190 ft (57.9 m)
Deck width59 ft (18 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic35,000 (2024)
Projected traffic42,286 by 2044
Trucks21%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$10 million (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was I - 20 East over Cahaba River built?

It was built in 1984, making it 41 years old in 2025.

What condition is I - 20 East over Cahaba River 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 October 2024.

How much traffic does I - 20 East over Cahaba River carry?

About 35,000 vehicles per day (2024 count), of which roughly 21% are trucks.

How long is I - 20 East over Cahaba River?

The structure is 740 ft (225.6 m) long with a longest span of 190 ft (57.9 m) and a deck 59 ft wide.

Who owns I - 20 East over Cahaba River?

It is owned by the State Highway Agency.