With the Criteria - Sidesway command, the user can indicate whether a frame is Non-sway, Sway Sensitive or Non-Sway on Axis. Non-Sway on Axis refers to structures that are Non-Sway in one direction but Sway-sensitive in the other. When Non-Sway on Axis is selected the user must specify the range of member orientation, with respect to the global coordinate axes, for which the member is to be considered non-sway.

For BS5950:2000 the program can determine the sway state of a particular member axis if the Calculate (Per Load Combination) option is selected. When this option is applied the program will calculate the lateral story drifts at the position of each member being designed, for each floor. Drifts are calculated using only the factored notional load cases in each load combination. These drifts are then used to calculate λcr per 2.4.2.6, which if between 4.0 and 10.0 will then result in the member being designated as a sway-sensitive member in that axis. NOTE that the user will need to have created and analyzed notional load cases to make use of this option. Refer to the technical section for more information on calculating λcr for load combinations.

These settings affect the method by which the effective length Le is calculated for the lateral members

Modifying the Sidesway criteria after a Code Check has been performed will invalidate the results of that Code Check. The model will be redrawn on the screen in its original colors (rather than the Code Check colors) indicating that the Code Check must be re-run.

Refer to the Assign chapter for information on how this criterion can be overridden on a member-by-member basis.