Evaluation of Drift Demands for the Seismic Performance Assessment of Frames

Abstract

This study presents an evaluation of drift demands and their associated uncertainties for nondeteriorating regular moment resisting frame structures subjected to ordinary ground motions (i.e., without near-fault effects). The only source of uncertainty considered is the uncertainty due to differences in the frequency content of the ground motions. The information presented in this study is deemed to be useful for preliminary design and seismic performance assessment in which the performance targets of interest are those related to damage and loss of function (downtime). Thus, the focus is on ductility levels that are not so large that they cause significant cyclic deterioration in the components of the structural system. The dependence of drift demands (the maximum roof drift, the average of maximum story drifts, and the maximum story drift over the height) on relative ground motion intensity, fundamental period, and number of stories is investigated.