An upper-bound pushover analysis procedure for estimating the seismic demands of high-rise buildings

When evaluating the seismic demands of tall buildings, engineers are more likely to adopt simplified non-linear static analytical procedures, or pushover analyses, instead of the more complicated non-linear response history analysis. Since the conventional procedure has some drawbacks in predicting the inelastic seismic demands of high-rise buildings, some improved procedures have recently been investigated. In this paper, a new simplified pushover analysis procedure, which considers higher mode effects, is proposed. The basic features of the proposed procedure are: the response spectrum-based higher mode displacement contribution ratios, a new formula for determining the lateral load pattern and the upper-bound (absolute sum) modal combination rule for determining the target roof displacement. Five different-height buildings are used as examples to illustrate the application of the proposed procedure. Three other types of analysis are performed for the purposes of comparison. It will be demonstrated that the proposed procedure can more precisely estimate important response attributes of tall buildings, such as roof displacements, story drift ratios and plastic hinge rotations.