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

Sahman Soleimani,Abdolreza S. Moghadam,Armin Aziminejad

doi:10.1007/s10518-022-01324-z

Abstract

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.

Highlights

Incremental dynamic analysis (IDA) is a parametric analysis method used for seismic assessment of structures (Vamvatsikos and Cornell 2002)
The median drift ratios predicted by based pushover (BEP) over the elevations of the buildings are compared with those of the exact nonlinear dynamic analyses (NDA) for a wide range of ground motion intensity levels
The curves for IDA and BEP were obtained from 12 NDAs on average, covering the structural behavior from the elastic domain to the point of collapse

Summary

Introduction

Incremental dynamic analysis (IDA) is a parametric analysis method used for seismic assessment of structures (Vamvatsikos and Cornell 2002). Han and Chopra (2006) proposed an incremental version of the well-known modal pushover analysis (MPA) (Chopra and Goel 2002) to produce approximate IDA curves. This method has the advantage of considering the contribution of higher modes. The distortions occasionally encountered in capacity curves of higher modes often cause disruption in the process of MPA (FEMA 2005) This is especially the case when the building is subjected to ground motion records causing significant nonlinearity in higher modes. Dolšek and Fajfar (2004) introduced an incremental version of the N2 method (Fajfar 2000), called IN2, to predict approximate IDA curves, which showed reasonable accuracy in assessing in-filled concrete frames. The method was tested on a 4-story RC building, achieving good estimates of the exact IDA curves

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