US Bridges

Grand Caillou RD over Platt Bayou

PoorPosted for load

Terrebonne Parish, Louisiana · 0119 Log MI from in · Structure no. 025529205904391

Built
1978
47 years old
Condition
Poor
inspected April 2023
Type
Slab
Concrete
Length
114 ft
6 main spans
Daily traffic
128
2023 count
Owner
County
County Highway Agency

About this bridge

Grand Caillou RD over Platt Bayou is a concrete slab carrying Grand Caillou RD over Platt Bayou in Terrebonne Parish, Louisiana. It was built in 1978, so it is 47 years old, older than the Louisiana average of 43 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for load restriction.

It carries about 128 vehicles a day, projected to reach 140 by 2043. The structure is 114 ft (34.7 m) long and 27 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesGrand Caillou RD
CrossesPlatt Bayou
Location0119 Log MI from in
RouteCounty Highway 0
CountyTerrebonne Parish
StateLouisiana
Coordinates29.34268, -90.73067
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating12.9 US tons
Inventory rating9.6 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, precast panels
Main spans6
Design loadHS 20
Structure length114 ft (34.7 m)
Longest span19 ft (5.8 m)
Deck width27 ft (8.3 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic128 (2023)
Projected traffic140 by 2043
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was Grand Caillou RD over Platt Bayou built?

It was built in 1978, making it 47 years old in 2025.

What condition is Grand Caillou RD over Platt Bayou in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in April 2023.

How much traffic does Grand Caillou RD over Platt Bayou carry?

About 128 vehicles per day (2023 count).

How long is Grand Caillou RD over Platt Bayou?

The structure is 114 ft (34.7 m) long with a longest span of 19 ft (5.8 m) and a deck 27 ft wide.

Who owns Grand Caillou RD over Platt Bayou?

It is owned by the County Highway Agency.