SEISMIC ANALYSIS OF RC OPEN GROUND STORY BUILDINGS IN ZONE-V

Open ground floors (also known as soft storey) buildings are commonly used in the urban environment today, as they provide parking which is most needed. This type of building shows a relatively greater tendency to collapse during earthquakes because of the soft ground floor effect. The great lateral movement is induced in the first level of these buildings producing large curvatures in the columns of a floor of the ground floor Indian Standard IS 1893: 2002 allows the analysis of open ground floor building structures without taking into account infill stiffness but with a factor of multiplication 2.5 in compensation for the discontinuity of the stiffness. As per the code the columns and beams of the open aground storey are to be designed for 2.5 times the storey shears and moments assessed under aseismic loads of bare frames (i.e., without considering the infill stiffness). However, as experienced by the engineers at design offices, the multiplication factor of 2.5 is not accurate for low rise buildings designs these days. Infill walls can be modelled in commercially available software ETABS using two-dimensional area element with appropriate material properties for linear elastic analysis. But this type of modelling may not work for non-linear analysis since the anon-linear material properties for a two-dimensional orthotropic element is not very well understood. Seismic evaluation of an assumed reinforced concrete (RC) framed building would invariably require a non-linear analysis and is performed in this thesis in detail to capture the behaviour of such building structures..