Perforation of cross-sections
The perforation may be defined for all types of cross-sections except solid ones, CHS and trapezoidal sheeting profiles. Holes may be specified in all parts of the cross-section. The perforation is specified by the number of holes, their diameter, spacing and distance from edge. Input of holes is limited in the way, that it isn't possible to specify unsymmetrical holes for symmetrical cross-section (e.g. left and right parts of flange have to be perforated in the same way). The reduced cross-sectional characteristics are considered in the design. The change of the centre of gravity is ignored in the design.
The resistance of perforated cross-section may be higher than the resistance of the original cross-section, as the ultimate strength of steel fu is considered in the analysis. The analysis of the cross-section without holes is based on the yield strength fy. The cross-sectional characteristics are calculated in a different way for certain types of loads. All unfilled holes are considered for the combination of axial force and bending moments. Filled holes are considered only in cross-sectional parts, that are in tension. All holes without any exception are considered in the shear analysis.