US Bridges

Duplantis Bridge over Petit Caillou Bayou

GoodPosted for load

Terrebonne Parish, Louisiana · 0144 Log MI from in · Structure no. 025529318903591

Built
1973
52 years old
Condition
Good
inspected June 2023
Type
Movable - Lift
Steel
Length
136 ft
1 main span
Daily traffic
5,180
2022 count
Owner
County
County Highway Agency

About this bridge

Duplantis Bridge over Petit Caillou Bayou is a steel movable - lift carrying Duplantis Bridge over Petit Caillou Bayou in Terrebonne Parish, Louisiana. It was built in 1973, so it is 52 years old, older than the Louisiana average of 43 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. Its operating status is: posted for load restriction.

It carries about 5,180 vehicles a day, projected to reach 5,698 by 2042. The structure is 136 ft (41.5 m) long and 29 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

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CarriesDuplantis Bridge
CrossesPetit Caillou Bayou
Location0144 Log MI from in
RouteCounty Highway 0
CountyTerrebonne Parish
StateLouisiana
Coordinates29.52989, -90.59979
Functional classRural Local

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJune 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 adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating23.9 US tons
Inventory rating18.5 US tons

Structure

Structure typeMovable - Lift
MaterialSteel
DeckOpen grating
Main spans1 (+4 approach)
Design loadH 15
Structure length136 ft (41.5 m)
Longest span55 ft (16.8 m)
Deck width29 ft (8.9 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deck15 ft (4.6 m)

Traffic and service

Average daily traffic5,180 (2022)
Projected traffic5,698 by 2042
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 proposedNone recorded
Estimated improvement cost—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was Duplantis Bridge over Petit Caillou Bayou built?

It was built in 1973, making it 52 years old in 2025.

What condition is Duplantis Bridge over Petit Caillou Bayou in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in June 2023.

How much traffic does Duplantis Bridge over Petit Caillou Bayou carry?

About 5,180 vehicles per day (2022 count).

How long is Duplantis Bridge over Petit Caillou Bayou?

The structure is 136 ft (41.5 m) long with a longest span of 55 ft (16.8 m) and a deck 29 ft wide.

Who owns Duplantis Bridge over Petit Caillou Bayou?

It is owned by the County Highway Agency.