Incremental modified pushover analysis

The recently developed Incremental Dynamic Analysis (IDA) requires nonlinear time history analyses at different levels of intensity of an ensemble of ground motions, which is time‐consuming due to the high computational efforts involved. In the current study, a simplified method named as Incremental Modified Pushover (IMP) is developed and evaluated. In this method, the response of the structure is obtained using one pushover analysis at any specified level of ground motion intensity. The associated higher mode effects are explicitly considered when determining target roof displacement and lateral load pattern. In the bilinear idealization of the pushover curves, a new approach has been used. Moment resisting steel frames with 4, 8, 12 and 16 stories, as well as their corresponding soft‐story models are used for verifying the proposed method. The studied frames were subjected to seventeen different scaled earthquake ground motions. The results of the presented method, IMP, are verified in terms of maximum roof displacement, maximum inter‐story drift and maximum plastic hinge rotation at different ground motion intensities. The results show that the IMP method gives higher response values compared with IDA, which can be viewed as being more conservative. Copyright © 2008 John Wiley & Sons, Ltd.