Seismic Analysis of Vertically Irregular Buildings

The greatest challenge for any structural engineer in today's scenario is to design seismic-resistant structures. A regular building, i.e. having mass and stiffness uniformly distributed through its height behaves normally. The presence of vertical irregular frame subject to devastating earthquakes is a matter of concern. Points of sudden change in stiffness, mass and strength in buildings are known as weak points. For the design of safe irregular buildings it is necessary to study the effect of irregularity on the response of buildings to lateral loads. Here we study the proportional distribution of lateral forces evolved through seismic action in each storey level due to changes in mass and stiffness of frame on vertically irregular structures. The effect of mass and stiffness irregularity of G + 10-storeyed vertical geometric irregular building is studied using finite element method-based software. Two methods of analysis, namely linear static and linear dynamic analysis are used to evaluate response of the structure in the form of storey shear, storey displacement and storey drift. Responses are plotted and compared, and conclusions have been made from the results.