Methodology & Impact of Vertical Irregularities on Seismic Responses in Tall Buildings: A Comparative Analysis

The vulnerability of tall buildings to earthquake damage is influenced by numerous factors, including irregularities in their design and construction. Irregular structures, characterized by variations in geometry, mass distribution, and stiffness, are particularly susceptible to seismic-induced damage. In this study, we conduct an in-depth analytical examination of vertical irregularities, encompassing stiffness, mass, and vertical geometry variations. Ten structural models are considered, including an 11-story moment-resisting frame (MRF) building and its derivative models, to investigate the effects of these irregularities. Response spectrum analysis, based on the design response spectrum from NBC 105:2020, is performed on each model, and the building’s responses are compared. Our findings reveal significant variations in the responses of tall buildings when different vertical irregularities are introduced. Notably, vertical geometry irregularities have a more pronounced effect on responses compared to mass and stiffness irregularities in specific storeys. This research provides valuable insights into the seismic behavior of tall buildings and their vulnerability to vertical irregularities.