DefinePK

Abstract

In Indian construction scenario, majority of medium rise structures is of framed reinforced concrete structural system with masonry infills. Further, depending on the functional requirements, the floor heights are not uniform thereby introducing vertical stiffness irregularities. The computer modeling using software normally takes care of the stiffness irregularity but designers seldom model the masonry infills. In usual practice, while the mass of the infills is considered, their stiffness contribution is ignored. Moreover, with the increasing requirement to make the structure fully earthquake resistant, behavior of structural system which has been designed using Response Spectrum method has to be studied in the nonlinear range using Pushover analysis. This paper reports the findings of exhaustive analysis carried out on a ground plus eleven story single bay frame with and without infills, and with and without vertical stiffness irregularity in the linear and nonlinear range. Further the study has been expanded to include the effect of different seismic zones as classified in Indian codes.