ABSTRACT
The forces required to cause a unit rotation or translation in the transverse direction at one end of a member decrease when the member is subjected to axial compressive force, and conversely increase if the axial force is tensile. When the axial forces in members of frames are relatively high, the change in stiffness arising from bending by the axial force can be of importance. This effect of the axial force is important in slender members only, and is referred to as the beam–column effect (or, casually, P-delta effect).
