In high rise building or multi storey building, soft
storey construction is a typical feature because of
urbanization and the space occupancy considerations.
Reinforced concrete framed buildings with in-fills are usually
analyzed as bare frame, without considering the strength and
stiffness contributions of the in-fills. However when subjected
to a strong lateral loads, infill panels tends to interact with
bonding frame and may induce a load resistance mechanism
that is not accounted for the design. These provisions reduce
the stiffness of the lateral load resisting system and a
progressive collapse becomes unavoidable in a severe
earthquake for such buildings due to soft storey. This storey
level containing the concrete columns were unable to provide
adequate shear resistance, hence damage and collapse are
most often observed in soft storey buildings during the
earthquake. Open first storey is a typical feature in the modern
multi-storey constructions in urban India. Such features are
highly undesirable in buildings built in seismically active
areas; this has been verified in numerous experiences of strong
shaking during the past earthquakes. Response spectrum
analysis is chosen for the analysis of the model since it
provides response to the applied loads and spectra conditions.
In the current study the focus is on the performance and
behavior of a structure with soft storey at different floors with
the help of response spectrum method. For analysis purpose,
six different cases of model are studied using ETABS V.16.03. A
G+20 building with simple square plan is considered, as per IS
456:2000 and IS 1893:2002.