SEISMIC RESPONSE OF VERTICALLY IRREGULAR RC FRAME WITH MASS IRREGULARITY

Structural engineer's greatest challenge in today's scenario is constructing seismic resistant structure. Uncertainties involved and behavior studies are vital for all civil engineering structures. The presence of vertical irregular frame subject to devastating earthquake is matter of concern. The present paper attempts to investigate the proportional distribution of lateral forces evolved through seismic action in each storey level due to changes in mass of frame on vertically irregular frame. As per the Bureau of Indian Standard (BIS) 1893:2002 (part1) provisions, a G+10 vertically irregular building is modeled as an simplified lump mass model for the analysis with mass irregularities at third & seventh floor. To response parameters like story drift, story deflection and story shear of structure under seismic force under the linear static & dynamic analysis is studied. This analysis shows focuses on the base shear carrying capacity of a structure and performance level of structure under sever zone of India. The result remarks the conclusion that, a building structure with mass irregularity provides instability and attracts huge storey shear. A proportionate amount of mass is advantageous to control over the storey and base shear. The soft computing tool and commercial software CSI-ETABS (version 9.7) is used for modeling and analysis.