US Bridges

LA0631 over Bayou Desallemand

FairPosted for load

St. Charles Parish, Louisiana · .4 MI West of LA 632 · Structure no. 024508450600001

Built
1935
90 years old
Condition
Fair
inspected July 2023
Type
Movable - Swing
Steel
Length
542 ft
1 main span
Daily traffic
1,834
2021 count
Owner
State
State Highway Agency

About this bridge

LA0631 over Bayou Desallemand is a steel movable - swing carrying LA0631 over Bayou Desallemand in St. Charles Parish, Louisiana. It was built in 1935, so it is 90 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 1,834 vehicles a day, roughly 13% of them trucks, projected to reach 2,017 by 2041. The structure is 542 ft (165.2 m) long and 30 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesLA0631
CrossesBayou Desallemand
Location.4 MI West of LA 632
RouteState Highway 631
CountySt. Charles Parish
StateLouisiana
Coordinates29.82355, -90.47711
Functional classUrban Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating11.8 US tons
Inventory rating8.9 US tons

Structure

Structure typeMovable - Swing
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+9 approach)
Design loadH 15
Structure length542 ft (165.2 m)
Longest span111 ft (33.8 m)
Deck width30 ft (9 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,834 (2021)
Projected traffic2,017 by 2041
Trucks13%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusEligible 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 LA0631 over Bayou Desallemand built?

It was built in 1935, making it 90 years old in 2025.

What condition is LA0631 over Bayou Desallemand 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 LA0631 over Bayou Desallemand carry?

About 1,834 vehicles per day (2021 count), of which roughly 13% are trucks.

How long is LA0631 over Bayou Desallemand?

The structure is 542 ft (165.2 m) long with a longest span of 111 ft (33.8 m) and a deck 30 ft wide.

Who owns LA0631 over Bayou Desallemand?

It is owned by the State Highway Agency.