Effects of Ground Motion Directionality on the Seismic Behavior of Mid-rise Concrete Buildings with Considering Unequal Live-Load Distribution in Height

The incident angle of ground motion is one of the sources of uncertainty in the seismic response of buildings. Moreover, understanding the structural response to the impose ground motion may cause significant changes in the maximum response of buildings. In order to investigate the influence of the spatial distribution of orthogonal components of earthquake strong motion on the structural responses, three 15-story buildings were analyzed in this study using the time-history method. A significant live load (750 kg/m2) is imposed at different vertical levels of the structures. The imposed load was combined with ground motion excitations in the range of 0 to 90 degrees. The response of structure was investigated using roof drift index and inter-story drift ratio. Results demonstrate the orientation of seismic excitation and considering the maximum values of roof drift index, which correspond to the critical direction increase roof drift index between 8 to 12 percent. Furthermore, the inter-story drift ratio increased between 30 to 33 percent due to the orientation of excitation and considering the maximum values of the inter-story drift ratio, which correspond to the critical direction.