US Bridges

Blackmud RD over Colyell Creek

FairPosted for load

Livingston Parish, Louisiana · 2.5 M N/E of 447 Exit · Structure no. 623230284905041

Built
1998
27 years old
Condition
Fair
inspected August 2024
Type
Slab
Concrete
Length
76 ft
4 main spans
Daily traffic
300
2022 count
Owner
County
County Highway Agency

About this bridge

Blackmud RD over Colyell Creek is a concrete slab carrying Blackmud RD over Colyell Creek in Livingston Parish, Louisiana. It was built in 1998, so it is 27 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. Its operating status is: posted for load restriction.

It carries about 300 vehicles a day, projected to reach 330 by 2042. The structure is 76 ft (23.2 m) long and 27 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesBlackmud RD
CrossesColyell Creek
Location2.5 M N/E of 447 Exit
RouteCounty Highway 0
CountyLivingston Parish
StateLouisiana
Coordinates30.47397, -90.83748
Functional classRural 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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating27.1 US tons
Inventory rating21.1 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 width27 ft (8.1 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic300 (2022)
Projected traffic330 by 2042
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Blackmud RD over Colyell Creek built?

It was built in 1998, making it 27 years old in 2025.

What condition is Blackmud RD over Colyell Creek 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 Blackmud RD over Colyell Creek carry?

About 300 vehicles per day (2022 count).

How long is Blackmud RD over Colyell Creek?

The structure is 76 ft (23.2 m) long with a longest span of 19 ft (5.8 m) and a deck 27 ft wide.

Who owns Blackmud RD over Colyell Creek?

It is owned by the County Highway Agency.