US Bridges

LA0661 over Navigation Canal

Fair

Terrebonne Parish, Louisiana · .01 MI North of LA 315 · Structure no. 025508550800001

Built
1962
63 years old
Condition
Fair
inspected July 2023
Type
Movable - Swing
Steel
Length
364 ft
1 main span
Daily traffic
10,945
2021 count
Owner
State
State Highway Agency

About this bridge

LA0661 over Navigation Canal is a steel movable - swing carrying LA0661 over Navigation Canal in Terrebonne Parish, Louisiana. It was built in 1962, so it is 63 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 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 10,945 vehicles a day, roughly 11% of them trucks, projected to reach 12,039 by 2041. The structure is 364 ft (110.9 m) long and 33 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesLA0661
CrossesNavigation Canal
Location.01 MI North of LA 315
RouteState Highway 661
CountyTerrebonne Parish
StateLouisiana
Coordinates29.56795, -90.71613
Functional classUrban Minor Arterial

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no 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 adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating25.4 US tons
Inventory rating19.6 US tons

Structure

Structure typeMovable - Swing
MaterialSteel
DeckOpen grating
Main spans1 (+6 approach)
Design loadH 15
Structure length364 ft (110.9 m)
Longest span240 ft (73.2 m)
Deck width33 ft (10.1 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deck20 ft (6.1 m)

Traffic and service

Average daily traffic10,945 (2021)
Projected traffic12,039 by 2041
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.5 million
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was LA0661 over Navigation Canal built?

It was built in 1962, making it 63 years old in 2025.

What condition is LA0661 over Navigation Canal 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 LA0661 over Navigation Canal carry?

About 10,945 vehicles per day (2021 count), of which roughly 11% are trucks.

How long is LA0661 over Navigation Canal?

The structure is 364 ft (110.9 m) long with a longest span of 240 ft (73.2 m) and a deck 33 ft wide.

Who owns LA0661 over Navigation Canal?

It is owned by the State Highway Agency.