I0010

over W ATCHAFALAYA FLOODWAY

2.5 MI EAST OF LA 347, St. Martin Parish, Louisiana

Condition

Fair

Year Built

1971

Daily Traffic

37,370

Length

2,344 ft

About This Bridge

I0010 carries traffic over W ATCHAFALAYA FLOODWAY in St. Martin Parish, Louisiana. Built in 1971, this structure is 55 years old, placing it among the older bridges still in active service. The bridge features steel continuous construction with a girder and floorbeam design, a combination chosen by engineers to meet the specific requirements of this crossing.

Approximately 37,370 vehicles cross this bridge daily, representing moderate traffic volumes typical of important regional connectors. This level of usage requires regular monitoring to ensure continued safe operation. Commercial trucks account for 22% of all crossings. This heavy commercial usage significantly impacts structural wear, as a single fully-loaded truck can cause as much deck wear as thousands of passenger vehicles. Transportation planners factor this into maintenance scheduling and budget allocation.

The bridge is currently rated in fair condition based on federal inspection criteria established by the Federal Highway Administration. The structure meets current safety standards for its designated use and load capacity. With a total length of 2,344 feet, this is a major span requiring specialized engineering expertise for inspection and maintenance. Longer bridges present unique challenges including thermal expansion, wind loads, and more complex structural analysis.

The construction materials used in this bridge were selected based on engineering requirements, cost considerations, and local conditions at the time of construction.

Federal law requires that all highway bridges be inspected at least every 24 months by qualified inspectors following the National Bridge Inspection Standards (NBIS). Some bridges with known issues or unusual characteristics may be inspected more frequently. Inspection data is reported to the National Bridge Inventory, a database maintained by the Federal Highway Administration that tracks the condition of all public highway bridges in the United States. This bridge data is sourced from that federal database and reflects the most recent available inspection results.

Condition Ratings

6

Deck Condition

Satisfactory

6

Superstructure

Satisfactory

6

Substructure

Satisfactory

7

Channel & Protection

Good

6

Lowest Rating

Determines condition category

NBI condition ratings range from 0 (failed) to 9 (excellent). Ratings of 4 or below are considered poor. The overall condition category is determined by the lowest individual component rating.

The fair condition rating of 6 indicates satisfactory condition with minor section loss or deterioration.

For a structure built in 1971, this condition level is expected given the bridge's age and usage patterns.

Bridge Details

Steel Continuous is the primary structural material, which influences maintenance requirements and expected lifespan. The girder and floorbeam design was selected based on span requirements, load capacity needs, and site conditions at the time of construction. Maintenance responsibility falls to State Highway Agency.

Construction

Year Built1971
MaterialSteel Continuous
Design TypeGirder and Floorbeam
OwnerState Highway Agency

Dimensions

Total Length2,344 ft (714.5 m)
Max Span57 ft (17.5 m)
Deck Width4 ft
Deck Area93,593 sq ft

Span dimensions affect structural design choices and load distribution. The deck area of 93,593 sq ft determines surface maintenance scope.

Classification

Route TypeInterstate
Route Number1
Lanes On Bridge2
Lanes Under Bridge4

Status

Toll BridgeNo
Historical SignificanceNot eligible
Scour Critical8
Detour Length1 mi (2 km)

Traffic Data

Traffic volume data helps engineers assess bridge wear patterns and plan maintenance schedules. Average Daily Traffic (ADT) counts are updated periodically and represent typical weekday usage.

37,370

Avg Daily Traffic (2021)

Vehicles per day crossing this bridge

22%

Truck Traffic

Commercial vehicle percentage

41,107

Projected Future ADT

Estimated future demand

This bridge carries approximately 37,370 vehicles per day, translating to roughly 13,640,050 crossings annually. This moderate traffic level is typical for regional connectors.

Commercial trucks comprise 22% of traffic. Heavy vehicles cause disproportionate wear—a single fully loaded truck can have the impact of thousands of passenger cars on bridge deck surfaces. This high percentage of truck traffic may accelerate deterioration of deck surfaces and structural components.

Traffic projections estimate future volumes of 41,107 vehicles daily, a 10% increase from current levels. These projections inform capacity planning and potential upgrade requirements.

Load Ratings

Load ratings determine what weight this bridge can safely support. These values are critical for routing heavy vehicles and issuing overweight permits.

Operating Rating

5.2 tons

Maximum allowable load for special permits

Inventory Rating

3.1 tons

Load level for normal traffic

The operating rating of 5.2 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 3.1 tons is the safe load limit for everyday traffic without restrictions. These relatively low ratings may result in posted weight limits or route restrictions for heavy vehicles.

5-Year Condition Trend

Stable

Condition has remained relatively stable since 2020

Data: 2020-2024 FHWA National Bridge Inventory

Location

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30.981944, -92.650000

Identification

Structure Number035004500609931
NBI IDLA-035004500609931
State FIPS22
County FIPS099

Explore More

Data Source: Federal Highway Administration (FHWA) National Bridge Inventory 2024

Bridge inspection data is typically updated every 24 months. Conditions may have changed since the last inspection.

“Structurally deficient” does not mean a bridge is unsafe or likely to collapse. It indicates that one or more key structural elements are in poor or worse condition. Bridges are inspected regularly and may have load restrictions in place.

This data is for informational purposes only and should not be used for route clearance or vehicle weight decisions.

I0010 over W ATCHAFALAYA FLOODWAY, Louisiana — Bridge Condition | BridgeReport.org | BridgeReport.org