Select section (rolled or plate girder). Check:
Previously treated as separate elements, the 4th Edition mandates: Select section (rolled or plate girder)
An engineer using the 2021 guide would follow this structured approach: Category A for base metal
The 4th Edition provides a new closed-form solution for bending of the top flange under the rail wheel. This is not covered in standard AISC manuals. not the maximum stress alone.
Fatigue is the governing design criterion for heavy-duty Class D and E cranes. The 4th edition aligns fatigue provisions with AISC Specification Appendix 3. It categorizes stress ranges into specific "Categories" (e.g., Category A for base metal, Category E for welded connections). The guide stresses that fatigue design relies on the stress range (the fluctuation between maximum and minimum stress), not the maximum stress alone.