US Bridges

St. Charles Bypass over Grand Coteau Bayou

FairPosted for load

Lafourche Parish, Louisiana · 0148 Log MI from Int · Structure no. 022929440904411

Built
1970
55 years old
Condition
Fair
inspected June 2023
Type
Slab
Concrete
Length
76 ft
4 main spans
Daily traffic
1,193
2020 count
Owner
County
County Highway Agency

About this bridge

St. Charles Bypass over Grand Coteau Bayou is a concrete slab carrying St. Charles Bypass over Grand Coteau Bayou in Lafourche Parish, Louisiana. It was built in 1970, so it is 55 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 5 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 1,193 vehicles a day, projected to reach 1,312 by 2040. The structure is 76 ft (23.2 m) long and 31 ft wide.

Location

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CarriesSt. Charles Bypass
CrossesGrand Coteau Bayou
Location0148 Log MI from Int
RouteCounty Highway 0
CountyLafourche Parish
StateLouisiana
Coordinates29.73327, -90.7347
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2023
Inspection intervalevery 12 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 adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating17.1 US tons
Inventory rating5.7 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, precast panels
Main spans4
Design loadHS 20
Structure length76 ft (23.2 m)
Longest span19 ft (5.8 m)
Deck width31 ft (9.5 m)
Roadway width28 ft (8.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,193 (2020)
Projected traffic1,312 by 2040
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
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 St. Charles Bypass over Grand Coteau Bayou built?

It was built in 1970, making it 55 years old in 2025.

What condition is St. Charles Bypass over Grand Coteau 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 June 2023.

How much traffic does St. Charles Bypass over Grand Coteau Bayou carry?

About 1,193 vehicles per day (2020 count).

How long is St. Charles Bypass over Grand Coteau Bayou?

The structure is 76 ft (23.2 m) long with a longest span of 19 ft (5.8 m) and a deck 31 ft wide.

Who owns St. Charles Bypass over Grand Coteau Bayou?

It is owned by the County Highway Agency.