Seismic assessment of RC frame building designed using gross and cracked section as per Indian standards

Abstract

This study presents the comparative seismic assessment of 2-, 4-, 8- and 12-storey RC frame buildings designed with gross/uncracked section (IS 1893-2002) and effective/cracked section (IS 1893-2016) properties of RC members using conventional force-based design approach. RC frames of similar height are designed using the same seismic base shear coefficient based on empirically obtained period of the building as recommended in IS 1893. All the considered frames are analyzed using nonlinear static pushover analysis and nonlinear time history analysis (NLTHA). The results of the pushover analysis and NLTHA show that the inter-storey drift at design load of RC frames designed using gross section property is well within the prescribed limit of maximum permissible inter-storey drift ratio. Whereas the inter-storey drift of RC frame designed using effective section properties of beams and columns for the force criteria alone is observed much higher as compared to RC frame designed using gross section and beyond the limit of maximum permissible inter-storey drift ratio. The RC frame buildings designed using the modified cracked section for the force as well as drift criteria of IS 1893 show the improved structural performance and its inter-story drift ratio observed is within the prescribed limit.