US Bridges

LA0117 over Flat Slough

Fair

Natchitoches Parish, Louisiana · 0.51 Mi. South of LA 120 · Structure no. 083501140308691

Built
1955
70 years old
Condition
Fair
inspected April 2024
Type
Slab
Concrete
Length
120 ft
6 main spans
Daily traffic
1,513
2021 count
Owner
State
State Highway Agency

About this bridge

LA0117 over Flat Slough is a concrete slab carrying LA0117 over Flat Slough in Natchitoches Parish, Louisiana. It was built in 1955, so it is 70 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 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 1,513 vehicles a day, roughly 14% of them trucks, projected to reach 1,664 by 2041. The structure is 120 ft (36.6 m) long and 29 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesLA0117
CrossesFlat Slough
Location0.51 Mi. South of LA 120
RouteState Highway 117
CountyNatchitoches Parish
StateLouisiana
Coordinates31.64466, -93.201
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating27.4 US tons
Inventory rating21.1 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans6
Design loadH 15
Structure length120 ft (36.6 m)
Longest span20 ft (6.1 m)
Deck width29 ft (8.8 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,513 (2021)
Projected traffic1,664 by 2041
Trucks14%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was LA0117 over Flat Slough built?

It was built in 1955, making it 70 years old in 2025.

What condition is LA0117 over Flat Slough 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 April 2024.

How much traffic does LA0117 over Flat Slough carry?

About 1,513 vehicles per day (2021 count), of which roughly 14% are trucks.

How long is LA0117 over Flat Slough?

The structure is 120 ft (36.6 m) long with a longest span of 20 ft (6.1 m) and a deck 29 ft wide.

Who owns LA0117 over Flat Slough?

It is owned by the State Highway Agency.