For tension only members, axial tension capacity is checked for the ultimate limit stress. For compression members, axial compression capacity is checked in addition to lateral buckling and ultimate limit stress. The largest slenderness ratio (λ) shall not be greater than 250 according to NS 11.7 Stability is checked as per the procedure of NS 12.3. The buckling curves of NS fig. 3 have been incorporated into the STAAD.Pro code check. The coefficient α (as per NS Table 10) can be specified in both directions through the use of parameters CY and CZ. In the absence of parameters CY and /or CZ, default a- value will be according to NS table 11.