US Bridges

W. 79th ST over Lafourche Bayou

FairPosted for load

Lafourche Parish, Louisiana · 0.01 MI E. of LA 1 · Structure no. 022929309902001

Built
1956
69 years old
Condition
Fair
inspected July 2023
Type
Movable - Swing
Steel
Length
192 ft
1 main span
Daily traffic
3,633
2021 count
Owner
County
County Highway Agency

About this bridge

W. 79th ST over Lafourche Bayou is a steel movable - swing carrying W. 79th ST over Lafourche Bayou in Lafourche Parish, Louisiana. It was built in 1956, so it is 69 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. Its operating status is: posted for load restriction.

It carries about 3,633 vehicles a day, projected to reach 3,996 by 2041. The structure is 192 ft (58.5 m) long and 24 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesW. 79th ST
CrossesLafourche Bayou
Location0.01 MI E. of LA 1
RouteCounty Highway 0
CountyLafourche Parish
StateLouisiana
Coordinates29.51508, -90.33364
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating24.7 US tons
Inventory rating19 US tons

Structure

Structure typeMovable - Swing
MaterialSteel
DeckSteel plate
Main spans1 (+6 approach)
Design loadHS 15
Structure length192 ft (58.5 m)
Longest span84 ft (25.6 m)
Deck width24 ft (7.3 m)
Roadway width18 ft (5.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,633 (2021)
Projected traffic3,996 by 2041
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed5 mi (8 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$606,000
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was W. 79th ST over Lafourche Bayou built?

It was built in 1956, making it 69 years old in 2025.

What condition is W. 79th ST over Lafourche Bayou 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 W. 79th ST over Lafourche Bayou carry?

About 3,633 vehicles per day (2021 count).

How long is W. 79th ST over Lafourche Bayou?

The structure is 192 ft (58.5 m) long with a longest span of 84 ft (25.6 m) and a deck 24 ft wide.

Who owns W. 79th ST over Lafourche Bayou?

It is owned by the County Highway Agency.