SR71

over Chipola River

8.5mi North of Gulf Co., Calhoun County, Florida

Condition

Fair

Year Built

1947

Daily Traffic

2,600

Length

70 ft

About This Bridge

SR71 carries traffic over Chipola River in Calhoun County, Florida. Built in 1947, this structure is 79 years old, making it a historic structure that has served the community for generations. The bridge features steel continuous construction with a stringer/multi-beam or girder design, a combination chosen by engineers to meet the specific requirements of this crossing.

Approximately 2,600 vehicles cross this bridge daily, indicating lower traffic volumes common for local roads and rural routes. While traffic is lighter, these bridges still serve essential community transportation needs. Commercial trucks account for 15% of all crossings. This proportion of commercial traffic is typical for this roadway classification and is factored into the bridge's design load ratings.

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 70 feet, this is a shorter span typical of local road crossings, often carrying traffic over small streams, drainage channels, or other roadways.

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

5

Deck Condition

Fair

6

Superstructure

Satisfactory

5

Substructure

Fair

6

Channel & Protection

Satisfactory

5

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 5 indicates some deterioration that warrants monitoring but doesn't affect structural integrity.

For a structure built in 1947, this condition level is expected given the bridge's age and usage patterns. If this bridge were closed, traffic would face a detour of approximately 7 miles, underscoring the importance of maintaining this crossing.

Bridge Details

Steel Continuous is the primary structural material, which influences maintenance requirements and expected lifespan. The stringer/multi-beam or girder 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 Built1947
MaterialSteel Continuous
Design TypeStringer/Multi-beam or Girder
OwnerState Highway Agency

Dimensions

Total Length70 ft (21.2 m)
Max Span8 ft (2.5 m)
Deck Width3 ft
Deck Area2,017 sq ft

Span dimensions affect structural design choices and load distribution. The deck area of 2,017 sq ft determines surface maintenance scope.

Classification

Route TypeState Highway
Route Number71
Lanes On Bridge2
Lanes Under Bridge

Status

Toll BridgeNo
Historical SignificanceNot eligible
Scour Critical7
Detour Length7 mi (11 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.

2,600

Avg Daily Traffic (2022)

Vehicles per day crossing this bridge

15%

Truck Traffic

Commercial vehicle percentage

4,511

Projected Future ADT

Estimated future demand

This bridge carries approximately 2,600 vehicles per day, translating to roughly 949,000 crossings annually. Lower traffic volumes generally result in less structural wear over time.

Commercial trucks comprise 15% 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.

Traffic projections estimate future volumes of 4,511 vehicles daily, a 74% 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

4.5 tons

Maximum allowable load for special permits

Inventory Rating

2.7 tons

Load level for normal traffic

The operating rating of 4.5 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 2.7 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

Declining

Condition has declined by 1.0 rating points since 2020

Data: 2020-2024 FHWA National Bridge Inventory

Location

Loading map...

30.640833, -86.272500

Identification

Structure Number470005
NBI IDFL-470005
State FIPS12
County FIPS013

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.

SR71 over Chipola River | Florida