SH 73/SH 87 NB

over COW BAYOU

0.40 MI S OF SH 62, Orange County, Texas

Condition

Poor

Year Built

1941

Daily Traffic

13,049

Length

80 ft

About This Bridge

SH 73/SH 87 NB carries traffic over COW BAYOU in Orange County, Texas. Built in 1941, this structure is 85 years old, making it a historic structure that has served the community for generations. The bridge features steel construction with a movable - swing design, a combination chosen by engineers to meet the specific requirements of this crossing.

Approximately 13,049 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 7% 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 poor condition based on federal inspection criteria established by the Federal Highway Administration. It is classified as structurally deficient, meaning one or more components have received a rating of 4 or below on the 0-9 scale. This designation indicates significant deterioration that warrants attention, though the bridge remains safe for travel within its posted limits. Structurally deficient does not mean unsafe—rather, it signals that repairs or replacement should be prioritized in transportation planning. With a total length of 80 feet, this is a shorter span typical of local road crossings, often carrying traffic over small streams, drainage channels, or other roadways.

Steel bridges provide high strength-to-weight ratios, making them suitable for longer spans. However, they require ongoing protection against corrosion through painting or weathering steel designs. Inspectors pay close attention to connection points, fatigue cracking, and coating condition.

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

Structurally Deficient

This bridge has one or more component ratings of 4 or below, indicating significant deterioration that requires attention. The bridge remains safe for travel but may have load restrictions.

7

Deck Condition

Good

6

Superstructure

Satisfactory

4

Substructure

Poor

6

Channel & Protection

Satisfactory

4

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 substructure rating of 4 reflects significant wear in piers, abutments, or foundations.

For a structure built in 1941, the current condition reflects the cumulative effects of age, traffic, and environmental exposure. If this bridge were closed, traffic would face a detour of approximately 7 miles, underscoring the importance of maintaining this crossing.

Bridge Details

Steel is the primary structural material, which influences maintenance requirements and expected lifespan. The movable - swing 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 Built1941
Year Reconstructed2015
MaterialSteel
Design TypeMovable - Swing
OwnerState Highway Agency

Dimensions

Total Length80 ft (24.5 m)
Max Span15 ft (4.7 m)
Deck Width3 ft
Deck Area2,378 sq ft

Span dimensions affect structural design choices and load distribution. The deck area of 2,378 sq ft determines surface maintenance scope.

Classification

Route TypeState Highway
Route Number73
Lanes On Bridge2
Lanes Under Bridge

Status

Toll BridgeNo
Historical SignificanceOn National Register of Historic Places
Scour Critical8
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.

13,049

Avg Daily Traffic (2020)

Vehicles per day crossing this bridge

7%

Truck Traffic

Commercial vehicle percentage

17,220

Projected Future ADT

Estimated future demand

This bridge carries approximately 13,049 vehicles per day, translating to roughly 4,762,885 crossings annually. This moderate traffic level is typical for regional connectors.

Commercial trucks comprise 7% 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 17,220 vehicles daily, a 32% 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

5.4 tons

Maximum allowable load for special permits

Inventory Rating

3.3 tons

Load level for normal traffic

The operating rating of 5.4 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 3.3 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

Status Changes

  • Entered poor condition in 2021
  • Became structurally deficient in 2021

Data: 2020-2024 FHWA National Bridge Inventory

Location

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31.182500, -94.290278

Identification

Structure Number201810030601017
NBI IDTX-201810030601017
State FIPS48
County FIPS361

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.

SH 73/SH 87 NB over COW BAYOU | Texas