Effect of Position of Infill Wall for Seismic Analysis of Low Rise Open Ground Storey Building

Presence of infill walls in the frames alters the behaviour of the building under lateral loads. However, it is
common industry practice to ignore the stiffness of infill wall for analysis of framed building. Engineers
believe that analysis without considering infill stiffness leads to a conservative design. But this may not be
always true, especially for vertically irregular buildings with discontinuous infill walls. Hence, the
modelling of infill walls in the seismic analysis of framed buildings is imperative. Infill walls can be
modelled in commercial software 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 nonlinear material properties for a two-dimensional orthotropic element is not very well understood. Seismic
evaluation of an existing reinforced concrete (RC) framed building would invariably require a non-linear
analysis. Published literature in this area recommends a linear diagonal strut approach to model infill wall
for both linear (Equivalent Static Analysis and Response Spectrum Analysis) and nonlinear analyses
(Pushover Analysis and Time History Analysis).