Crane Runway Girder Calculator, AISC 360-22

What it checks

The module designs overhead crane runway girders using US Customary units (kips, in, ft, ksi). It applies AISC 360-22 Appendix 3 and CMAA #70/#74 standards to evaluate vertical, lateral, and longitudinal crane forces. The design method incorporates CMAA service classes and fatigue categories to determine structural adequacy. The sequence of checks begins with the application of CMAA impact factors for vertical and horizontal loads. The module then maps the crane service class to the appropriate fatigue category. It calculates the maximum moment and evaluates the allowable stress range against the number of total stress cycles. Finally, it assesses deflection limits and overall demand-to-capacity ratios to determine if the girder meets code requirements.

Inputs

Geometry - Span length and cross-sectional properties (in, ft).
Crane Service - CMAA service class (1-6) or letter-coded class (A-F), where A is standby and F is continuous severe.
Impact Factors - Vertical and horizontal impact percentages based on crane type (cab 25%, pendant 10%, special-duty 100%).
Fatigue Parameters - Total stress cycles (N) or loading condition from which cycles are derived.
Load Cases - Vertical, lateral, and longitudinal crane forces (kips).

What it reports

Threshold Stress Range - Fth value (ksi) from AISC 360-22 App. 3 Table A-3.1.
Fatigue Coefficient - Cf coefficient for finite-life fatigue, with units of (ksi)^3 × cycles for categories A-E' and (ksi)^6 × cycles for category F.
Stress Range Exponent - Exponent value (1/3 for A-E', 1/6 for F) per AISC 360-22 Eq. A-3-1.
Allowable Stress Range - Fsr (ksi) calculated as max(Fth, (Cf/N)^k) for the given number of cycles.
Demand-to-Capacity Ratios - DCR values for various checks; defaults to infinity if inputs are degenerate, causing the overall check to fail.
Deflection Limits - Verification of deflection against runway serviceability limits.

Code references

The engine cites AISC 360-22 Appendix 3 for fatigue calculations, specifically Table A-3.1 for threshold stress ranges and coefficients, and Equation A-3-1 for allowable stress range. It also references CMAA #70 and #74 for impact factors and service class definitions, including CMAA #70 §4.5 for the letter-coded service classes A through F.

Limits

The module handles degenerate inputs such as zero span or zero properties gracefully by guarding against division by zero and defaulting capacities to 0. It does not support non-US Customary units. The letter-coded CMAA class is optional and derived from the numeric service class if not provided. Results are engineering aids; the engineer of record is responsible for the design.

This module ships in the desktop app

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