US Bridges

Grants Mill Road over Cahaba River

FairPosted for load

Jefferson County, Alabama · At Grants Mill · Structure no. 007150

Built
1960
65 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
342 ft
3 main spans
Daily traffic
7,105
2023 count
Owner
County
County Highway Agency

About this bridge

Grants Mill Road over Cahaba River is a steel continuous stringer/multi-beam or girder carrying Grants Mill Road over Cahaba River in Jefferson County, Alabama. It was built in 1960, so it is 65 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. Its operating status is: posted for load restriction.

It carries about 7,105 vehicles a day, roughly 10% of them trucks, projected to reach 9,900 by 2043. The structure is 342 ft (104.2 m) long and 29 ft wide. If it were closed, the detour would be 24.2 mi (39 km).

Location

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CarriesGrants Mill Road
CrossesCahaba River
LocationAt Grants Mill
RouteCounty Highway 143
CountyJefferson County
StateAlabama
Coordinates33.5109, -86.65255
Functional classRural Major 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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating37.9 US tons
Inventory rating22.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3 (+2 approach)
Design loadH 15
Structure length342 ft (104.2 m)
Longest span100 ft (30.5 m)
Deck width29 ft (8.9 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,105 (2023)
Projected traffic9,900 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed24.2 mi (39 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$2.5 million (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Grants Mill Road over Cahaba River built?

It was built in 1960, making it 65 years old in 2025.

What condition is Grants Mill Road 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 July 2023.

How much traffic does Grants Mill Road over Cahaba River carry?

About 7,105 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Grants Mill Road over Cahaba River?

The structure is 342 ft (104.2 m) long with a longest span of 100 ft (30.5 m) and a deck 29 ft wide.

Who owns Grants Mill Road over Cahaba River?

It is owned by the County Highway Agency.