COMPARATIVE DYNAMIC ANALYSIS AND SEISMIC PERFORMANCE EVALUATION OF A MULTI-STOREY REINFORCED CONCRETE RESIDENTIAL BUILDING IN SEISMIC ZONE II AND ZONE V

Abstract

Earthquake-resistant design of reinforced concrete buildings requires explicit consideration of dynamic characteristics and regional seismic demand. This study presents a comparative Response Spectrum Analysis of an identical G+10 reinforced concrete residential building representing Seismic Zone II and Seismic Zone V in India. A three-dimensional model was developed in ETABS using an RC moment-resisting frame, M30 concrete, Fe500 reinforcement, a 25 m × 20 m regular plan, 3.0 m storey height, and fixed-base supports. Dead, live, and seismic actions were assigned in accordance with the Indian Standard provisions adopted in the source study. The response spectrum was defined for medium soil and 5% damping, and modal responses were combined using CQC where applicable. The fundamental period was 1.45 s in both cases, while the reported base shear increased from 1,280 kN in Zone II to 4,610 kN in Zone V, representing a 260.16% increase. Roof displacement increased from 36 to 126 mm, and maximum storey drift increased from 0.0014 to 0.0038. Base overturning moment increased from 18,450 to 66,420 kN•m. Storey stiffness remained unchanged because the structural geometry and material properties were identical. The results demonstrate that seismic zoning strongly affects force and deformation demand while leaving the inherent dynamic properties of the unchanged model essentially constant. The study emphasizes the need for enhanced member sizing, reinforcement, confinement, ductile detailing, and foundation resistance in higher seismic zones.