MCKEES ROCK BR RD
over CSX RR
MCKEES ROCKS BOTTOMS, Allegheny County, Pennsylvania
Condition
FairYear Built
1931
Daily Traffic
27,207
Length
61 ft
About This Bridge
MCKEES ROCK BR RD carries traffic over CSX RR in Allegheny County, Pennsylvania. Built in 1931, this structure is 95 years old, making it a historic structure that has served the community for generations. The bridge features steel construction with a arch - thru design, a combination chosen by engineers to meet the specific requirements of this crossing.
Approximately 27,207 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 6% 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 61 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
Deck Condition
Fair
Superstructure
Fair
Substructure
Fair
Channel & Protection
N/A
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 1931, this condition level is expected given the bridge's age and usage patterns. High traffic volumes on a bridge in fair or poor condition typically elevate its priority for rehabilitation or replacement in state transportation planning.
Bridge Details
Steel is the primary structural material, which influences maintenance requirements and expected lifespan. The arch - thru 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
Dimensions
Span dimensions affect structural design choices and load distribution. The deck area of 2,417 sq ft determines surface maintenance scope.
Classification
Status
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.
27,207
Avg Daily Traffic (2023)
Vehicles per day crossing this bridge
6%
Truck Traffic
Commercial vehicle percentage
24,404
Projected Future ADT
Estimated future demand
This bridge carries approximately 27,207 vehicles per day, translating to roughly 9,930,555 crossings annually. This moderate traffic level is typical for regional connectors.
Commercial trucks comprise 6% 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 24,404 vehicles daily, a decrease 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
5.9 tons
Maximum allowable load for special permits
Inventory Rating
3.5 tons
Load level for normal traffic
The operating rating of 5.9 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 3.5 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
↓DecliningCondition has declined by 1.0 rating points since 2020
Data: 2020-2024 FHWA National Bridge Inventory
Location
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41.227778, -81.121111
Identification
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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.