US Bridges

Waterproof Bridge over Black Bayou

Fair

Terrebonne Parish, Louisiana · LA 182 Southdown-Mandalay · Structure no. 025500000200854

Built
2009
16 years old
Condition
Fair
inspected April 2023
Type
Slab
Concrete
Length
100 ft
5 main spans
Daily traffic
610
2021 count
Owner
County
County Highway Agency

About this bridge

Waterproof Bridge over Black Bayou is a concrete slab carrying Waterproof Bridge over Black Bayou in Terrebonne Parish, Louisiana. It was built in 2009, so it is 16 years old, younger 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 610 vehicles a day, projected to reach 671 by 2041. The structure is 100 ft (30.5 m) long and 28 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesWaterproof Bridge
CrossesBlack Bayou
LocationLA 182 Southdown-Mandalay
RouteCounty Highway 0
CountyTerrebonne Parish
StateLouisiana
Coordinates29.56238, -90.7938
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 protection7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating63.9 US tons
Inventory rating26.5 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, precast panels
Main spans5
Design loadHS 20
Structure length100 ft (30.5 m)
Longest span20 ft (6.1 m)
Deck width28 ft (8.4 m)
Roadway width23 ft (7.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic610 (2021)
Projected traffic671 by 2041
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Waterproof Bridge over Black Bayou built?

It was built in 2009, making it 16 years old in 2025.

What condition is Waterproof Bridge over Black 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 April 2023.

How much traffic does Waterproof Bridge over Black Bayou carry?

About 610 vehicles per day (2021 count).

How long is Waterproof Bridge over Black Bayou?

The structure is 100 ft (30.5 m) long with a longest span of 20 ft (6.1 m) and a deck 28 ft wide.

Who owns Waterproof Bridge over Black Bayou?

It is owned by the County Highway Agency.