Moment capacity (Section) (Beams: AS 4100)

The (section) moment capacity check is performed according to AS 4100 clause 5.1 for the moment about the x-x axis (Mx) and about the y-y axis (My), at the point under consideration.

For (member) moment capacity refer to the section Lateral torsional buckling resistance (Member moment capacity).

Note that for all section types, the effective section modulus about the major axis (Z_ex) will be based on the minimum slenderness ratio considering both flange and web. Internally Tekla Structural Designer will calculate the following:

flange slenderness ratio, z_f = (λ_ey - λ_ef) / ( λ_eyf - λ_epf)
web slenderness ratio, z_w = (λ_eyw - λ_ew) / ( λ_eyw - λ_epw)

For sections which have flexure major class either Compact or Non-compact, the effective section modulus about the major axis (Zex) will then be calculated by:

Z_ex = Z_x + [MIN(z_f, z_w, 1.0) * (Z_c - Z_x)] where Z_c = MIN(S_x, 1.5 * Z_x)

Note that for Channel sections under minor axis bending:

if there is single curvature with the flange tips in compression then Z_ey will be based on Z_eyR
if there is single curvature with the web in compression then Z_ey will be based on Z_eyL
if there is double curvature then Z_ey will be based on the minimum of Z_eyR and Z_eyL