Based on a study of isolated restrained columns, and two-column panel frames, the often complicated mechanics of moment formations in the members are studdied using elastic second-order theory for the purpose of establishing a base on which procedures for moments due to sidesway can be evaluated. A distinction is made between moment developments in “supporting (bracing) sway columns” and “supported (braced) sway columns”. The primary objective is to derive improved slender column design expressions that are suitable in approximate design code formats. Both shear, end moments and maximum moments, applicable over the full range of axial loads, are considered. Proposals are presented that will allow more economical designs of framed columns with sway. Extended application to load combinations that include both gravity and sideways loading are also suggested.
Approximate end and maximum moment formulations for slender columns in frames with sway.