ABSTRACT
A new method to estimate the maximum interstory drift demand in multi-story buildings subjected to earthquake ground motions is presented. The method permits a rapid estimation of the maximum interstory drift for a given acceleration time history or for a given displacement response spectrum. The proposed method uses two steps. In the first step, the maximum roof displacement is computed from the spectral displacement and in the second step, the maximum interstory drift is calculated from the maximum roof displacement. The method is based on three amplification factors computed from the lateral displacements of simple cantilever beams with different deformation patterns. The first factor relates the spectral displacement to the maximum roof displacement. The second factor relates the maximum roof displacement normalized by the height of the roof to the maximum interstory drift. The third factor relates the maximum interstory drift demand in a structure responding linearly to the maximum interstory drift demand in a structure with nonlinear response. Examples which demonstrate the use of the method on an eight-story and on a twelve-story reinforced concrete buildings and on a ten-story steel moment-resisting frame building are presented. Results computed with the simplified method are compared with those computed using linear and nonlinear time history analyses.
