THE EFFECT OF MASS IRREGULARITIES ON THE RESPONSE OF BUILDING

Abstract

Response and behavior of regular buildings has been specified to be better in most of the circumstances compare irregular ones. Different codes of practices for design and analysis of civil engineering structure specify different type of irregularities. Mass irregularity has been clearly defined by IS 1893 (Part 1) : 2002 to be a degrading influence on buildings. Apart from near presence of mass irregularity its location also is an important parameter. Different types of buildings such as framed buildings and/or stiff masonry constructions behave differently against earthquake forces. This difference is all the more prominent if mass irregularities are present. Considering advances in building constructions including more frequent construction of framed buildings it seems appropriate to study the effect of mass irregularity is such buildings. In the present study mass irregularity in framed building is considered. Due to irregular variation in mass the dynamic characteristics of the buildings are studied. In this study an aluminium framed model of a three storey building is taken. The mass irregularity is created by putting additional masses at different floor level. The eigenvalue analysis is undertaken for the framed model. The calculated eigenvalues are compared with values obtained from Etabs software analysis results. It is found that the results obtained in the cases of theoretical analysis, experimental programme and in the case of use of Etabs software are comparable.