Seismic Safety of Vertically Irregular Buildings: Performance of Existing Indicators

Abstract

Vertically irregular buildings are preferred by architects, mainly due to their aesthetics. Earthquake codes not only call for special attention to the design of such architectural forms but forbid the construction of these buildings in active seismic zones based on the degree of irregularity. It is under the purview of both architects and structural engineers to understand the inherent seismic risk associated with each type of vertically irregular buildings. This paper evaluates the seismic risk of selected vertically irregular buildings in terms of their fragility curves, annual probability of collapse, drift hazard curves, and confidence levels and correlates seismic risk with the corresponding degree of irregularity using different existing irregularity indicators. The results presented in this paper show that the existing irregularity indicators do not correlate with the associated seismic risk of vertically irregular buildings. This paper will help architects and engineers to choose appropriate building configuration without compromising their seismic safety.