SEISMIC EVALUATION OF MUTISTOREY BUILDING WITH SOFT STOREY

Abstract

Most of the reinforced concrete (RC) structures are not designed to resist major or moderate earthquakes. The designs of such building are regularly done by using gravity loading without considering the earthquake load. Thus these buildings are vulnerable during the event of an earthquake.. In present study bare frame and soft storey are modeled considering special and ordinary moment resisting frame (SMRF & OMRF) for medium soil profile under zone III. The masonry infill panels were modeled as equivalent diagonal strut seven and ten storey buildings are considered to represent medium and high rise buildings , equivalent static and response spectrum analysis was performed on bare frame, infill frames as brick and infill frame as solid concrete block using SAP 2000 V15 software. Nonlinear static pushover analysis carried out for default-hinge properties, M, PM, V and P hinges are applied to beam, column and strut available in some programs based on the FEMA-356 and ATC-40 guidelines. While such documents provide the hinge properties for several ranges of detailing, programs may implement averaged values. The performance of building frames were compared with bare frame, in terms of ductility, safety, and stiffness. The investigation concludes that the performance of the buildings having non-ductile moment resisting frames can be improved by adding infill walls and SMRF building models are found more resistant to earthquake loads as compared to the OMRF building models in terms of performance level, performance point and hinging variation the performance of building for OMRF lies in LS to CP range where as SMRF are found under life safety range ,this shows in high seismicity region the ductile detailing must be adopted to avoid the vulnerability of building for tremor loads.