Assessment of conventional nonlinear static procedures with FEMA load distributions and modal pushover analysis for high-rise buildings

The nonlinear static pushover analysis technique is mostly used in the performance-based design ofstructures and it is favored over nonlinear response history analysis. however, the pushover analysis withfema load distributions losses its accuracy in estimating seismic responses of long period structures whenhigher mode effects are important. some procedures have been offered to consider this effect. fema andmodal pushover analysis (mpa) are addressed in the current study and compared with inelastic responsehistory analysis. these procedures are applied to medium high-rise (10 and 15 storey) and high-rise (20 and30 storey) frames; efficiency and limitations of them are elaborated. mpa procedure present significantadvantage over fema load distributions in predicting storey drifts, but the both are thoroughly unsuccessfulto predict hinge plastic rotations with acceptable accuracy. it is demonstrated that the seismic demandsdetermined with mpa procedure will be unsatisfactory in nonlinear systems subjected to individual groundmotions which inelastic sdf systems related to significant modes of the buildings respond beyond the elasticlimit. therefore, it's inevitable to avoid evaluating seismic demands of the buildings based on individualground motion with mpa procedure.