US Bridges

LA1091 over I-12

Fair

St. Tammany Parish, Louisiana · LA1091 · Structure no. 625208522502221

Built
1970
55 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
270 ft
4 main spans
Daily traffic
15,094
2021 count
Owner
State
State Highway Agency

About this bridge

LA1091 over I-12 is a prestressed concrete stringer/multi-beam or girder carrying LA1091 over I-12 in St. Tammany 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 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 15,094 vehicles a day, roughly 8% of them trucks, projected to reach 16,603 by 2041. The structure is 270 ft (82.3 m) long and 30 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesLA1091
CrossesI-12
LocationLA1091
RouteState Highway 1091
CountySt. Tammany Parish
StateLouisiana
Coordinates30.30804, -89.7489
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment8: Equal to present desirable criteria
Operating rating75 US tons
Inventory rating37 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length270 ft (82.3 m)
Longest span88 ft (26.8 m)
Deck width30 ft (9.1 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15,094 (2021)
Projected traffic16,603 by 2041
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed3.1 mi (5 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$1.2 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was LA1091 over I-12 built?

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

What condition is LA1091 over I-12 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 September 2023.

How much traffic does LA1091 over I-12 carry?

About 15,094 vehicles per day (2021 count), of which roughly 8% are trucks.

How long is LA1091 over I-12?

The structure is 270 ft (82.3 m) long with a longest span of 88 ft (26.8 m) and a deck 30 ft wide.

Who owns LA1091 over I-12?

It is owned by the State Highway Agency.