Effect of Vertical and Mass Irregularity on RCC Structure Subjected to Seismic Loading

Abstract

he greatest challenge for any structural engineer in today’s scenario is to design seismic-resistant structures. The presence of vertical geometrical irregularity in building is a matter of concern when it is subjected to devastating earthquakes. Irregular configuration either in plan or in elevation is recognize as one of major causes of failure during earthquakes. The performance of a high rise building during strong earthquake motions depends on the distribution of stiffness, strength and mass along both the vertical and horizontal directions. If there is discontinuity in stiffness, strength and mass between adjoining storeys of a building then such a building is known as irregular building which triggers structural collapse of building when subjected to seismic loading. In present study G+14 story building with mass and vertical geometrical irregularity is analysed using static method and dynamic method in ETABS v 18.0.2 as per IS-1893-2016 (part 1). Analysis is performed for zone III. Also, response spectra analysis is done for torsion check in building. For dynamic analysis linear time history data of Bhuj, Mexico, and Kobe (Medium, Low and High Intensity) is used. Comparison of behaviour of irregular building is done with G+14 regular building in form of max storey shear, story displacement, story drift. From the analysis results, it is found that the mass irregularity has maximum storey shear, story displacement, story drift compares to regular and vertical geometrical irregular building. Also, sudden change in story shear is observed at set back level.