Abstract
The objective of the paper herein is to assess the fluctuation of axial load of columns within a moment-resisting medium-rise reinforced concrete building through nonlinear dynamic analyses employing a three-dimensional analytical building model. In this study, excitation of the ground motion is considered in the two different schemes: first expressed by a single component of motion, and second by two components of motion representing two horizontal components of strong ground motion. It is concluded that the fluctuation of axial load into the column under earthquake excitation is of significance in the seismic design on reinforced concrete buildings based on the ultimate strength concept. This fluctuation of axial load is verified critical in the corner columns. It is revealed that the loading scheme that one component of motion is applied to the building along its diagonal direction can generate a critical situation evaluated when applying two components of motion under realistic earthquake excitation.
