US Bridges

LA0520 over Middle Fork B Darbonne

Fair

Claiborne Parish, Louisiana · 9.4 Mi. N. of US 79 · Structure no. 041400000040450

Built
2017
8 years old
Condition
Fair
inspected August 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
320 ft
8 main spans
Daily traffic
532
2021 count
Owner
State
State Highway Agency

About this bridge

LA0520 over Middle Fork B Darbonne is a concrete continuous box beam or girders - multiple carrying LA0520 over Middle Fork B Darbonne in Claiborne Parish, Louisiana. It was built in 2017, so it is 8 years old, younger 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 532 vehicles a day, roughly 18% of them trucks, projected to reach 585 by 2041. The structure is 320 ft (97.5 m) long and 37 ft wide. If it were closed, the detour would be 11.2 mi (18 km).

CarriesLA0520
CrossesMiddle Fork B Darbonne
Location9.4 Mi. N. of US 79
RouteState Highway 520
Coordinates32.92704, -92.99493
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating68.6 US tons
Inventory rating52.9 US tons

Structure

MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans8
Design loadGreater than HL 93
Structure length320 ft (97.5 m)
Longest span40 ft (12.2 m)
Deck width37 ft (11.3 m)
Roadway width34 ft (10.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic532 (2021)
Projected traffic585 by 2041
Trucks18%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.2 mi (18 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was LA0520 over Middle Fork B Darbonne built?

It was built in 2017, making it 8 years old in 2025.

What condition is LA0520 over Middle Fork B Darbonne 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 August 2024.

How much traffic does LA0520 over Middle Fork B Darbonne carry?

About 532 vehicles per day (2021 count), of which roughly 18% are trucks.

How long is LA0520 over Middle Fork B Darbonne?

The structure is 320 ft (97.5 m) long with a longest span of 40 ft (12.2 m) and a deck 37 ft wide.

Who owns LA0520 over Middle Fork B Darbonne?

It is owned by the State Highway Agency.