US Bridges

LA0015 over Flat Slough Bridge

Fair

Richland Parish, Louisiana · 12.0 MI NW Franklin Par · Structure no. 054200260912051

Built
1954
71 years old
Condition
Fair
inspected July 2023
Type
Slab
Concrete
Length
60 ft
3 main spans
Daily traffic
2,382
2021 count
Owner
State
State Highway Agency

About this bridge

LA0015 over Flat Slough Bridge is a concrete slab carrying LA0015 over Flat Slough Bridge in Richland Parish, Louisiana. It was built in 1954, so it is 71 years old, older than the Louisiana average of 43 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 2,382 vehicles a day, roughly 16% of them trucks, projected to reach 2,620 by 2041. The structure is 60 ft (18.3 m) long and 31 ft wide. If it were closed, the detour would be 24.2 mi (39 km).

Location

Open in Google Maps
CarriesLA0015
CrossesFlat Slough Bridge
Location12.0 MI NW Franklin Par
RouteState Highway 15
CountyRichland Parish
StateLouisiana
Coordinates32.38817, -91.9629
Functional classRural Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 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
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating30.8 US tons
Inventory rating23.6 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length60 ft (18.3 m)
Longest span20 ft (6.1 m)
Deck width31 ft (9.5 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,382 (2021)
Projected traffic2,620 by 2041
Trucks16%
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

OwnerState Highway Agency
Maintained byState 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$327,000
NavigationNo navigation control on waterway

Frequently asked questions

When was LA0015 over Flat Slough Bridge built?

It was built in 1954, making it 71 years old in 2025.

What condition is LA0015 over Flat Slough Bridge 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 LA0015 over Flat Slough Bridge carry?

About 2,382 vehicles per day (2021 count), of which roughly 16% are trucks.

How long is LA0015 over Flat Slough Bridge?

The structure is 60 ft (18.3 m) long with a longest span of 20 ft (6.1 m) and a deck 31 ft wide.

Who owns LA0015 over Flat Slough Bridge?

It is owned by the State Highway Agency.