STAAD.Pro Help

Section Classification

The occurrence of local buckling of the compression elements of a cross-section prevents the development of full section capacity. It is therefore imperative to establish this possibility prior to determining the section capacities. Cross sections are classified in accordance with their geometrical properties and the stress pattern on the compression elements. For each load case considered in the design process, the program determines the section class and calculates the capacities accordingly. It is worth noting that the section class reported in the design output corresponds to the most critical load case among those being considered for design.

The program can design members with all section profiles that are of Class 1, 2, 3, or 4 as defined in section 3.5.1 of the code. However, the design of members that have a Class 5 section profile are limited to:
  • H-sections
  • Wide flange (with equal flanges or unequal flanges)
  • Tube sections