If the user has designated to have a member’s sway state (see 2.5.5.1) or amplified sway factor - kamp (see 2.6.6 ) calculated per load combination, then λ_cr needs to be calculated for that specific member axis for each combination. That is, the program needs to determine the building drift (and hence λ_cr) in the specific direction of the axis of the member we are considering for the current load combination.

Per the code λ_cr is required to be calculated using ONLY the factored notional load cases in the combination being considered. The notional loads are required to be applied in the direction of the axis being considered but the program only generates notional loads in the global orthogonal axes. Also, for some load combinations (those with lateral load cases) there are no notional load cases. As such the program needs to determine appropriate notional load cases and factors for combinations that do not contain them, and the program needs to adjust the notional load factors to achieve a notional load force that is oriented with the desired direction (member axis).The program addresses these issues as follows.