Shear capacity (Columns: AS 4100)
The shear check is performed according to AS 4100 clause 5.11.
For rolled and welded I- and H-sections, and for channel sections, an approximately uniform shear stress distribution is assumed when calculating major axis shear capacity (to clause 5.11.2). For these same sections a non-uniform shear stress distribution is assumed when calculating minor axis shear capacity (to clause 5.11.3), with a shear stress ratio f*vm / f*va = 1.5
For hollow sections a non-uniform shear stress distribution is assumed when calculating both major and minor axis shear capacity (to clause 5.11.3). For a CHS section the nominal shear yield capacity is taken per clause 5.11.4, while RHS and SHS sections assume a shear stress ratio f*vm / f*va = 3 * (2 * b + d) / [2 * (3 * b + d)] for major axis shear capacity and f*vm / f*va = 3 * (2 * d + b) / [2 * (3 * d + b)] for minor axis shear capacity.
Shear buckling
For rolled and welded I- and H-sections, and for channel sections, about the major axis, and also for RHS and SHS sections about both axes, when the shear panel depth to thickness ratio exceeds 82/√(fy/250) then the shear buckling capacity will be calculated per clause 5.11.5.1 assuming an unstiffened shear panel.
Note that for rolled and welded I- and H-sections, and for channel sections, fy will be taken as the yield strength of the web based on tw.