Bidirectional energy-based pushover procedure as a fast approach to establish approximate IDA curves under biaxial seismic excitations: an evaluation for medium- and high-rise buildings

This paper evaluates the accuracy of bidirectional energy-based pushover (BEP) procedure in predicting approximate incremental dynamic analysis (IDA) results for medium- and high-rise structures. BEP provides approximate IDA curves under the simultaneous effect of the two horizontal components of ground motions and is applicable to both symmetric- and asymmetric-plan buildings. The method has already proven useful in low-rise buildings, and this study aims to evaluate its suitability for mid- and high-rise structures. Six steel structures were considered in this evaluation in two groups of 9- and 20-story buildings, with each group consisting of a symmetric, a one-way asymmetric, and a two-way asymmetric-plan building. The assessment was performed for 22 pairs of far-field ground motion records. The results revealed that the accuracy of the method was satisfactory to produce approximate IDA curves for all structural models. The method had similar accuracy in the asymmetric models as it did in the symmetric models, although the accuracy showed a tendency to decrease as the height of the building increased. BEP also provided reasonable estimates of the demands in both 'flexible' and 'stiff sides' of the asymmetric buildings as well as the demands over the height of the buildings.