Effect of flexural demands in the leaner columns on the column buckling strength

Abstract

Leaner columns of steel frames are typically designed for axial load only and they are assumed not to contribute to the lateral stiffness of the system; however, a recent study revealed that under seismic loading leaner columns underwent significant flexural demands due to differential interstory drift demands along the building height that were not observed when traditional design methods were adopted. A parametric numerical study is conducted to quantify the reduction in column buckling strength due to these flexural demands that are not considered in design. An empirical column buckling strength reduction factor that accounts for the reduction in the column buckling strength due to flexural demands is proposed. This reduction factor can be easily implemented with traditional design approaches without considering the flexural demands in the leaner columns explicitly.