Seismic performance of reinforced concrete building frames on sloping ground retrofitted with steel and reinforced concrete jacketing

Buildings in the hilly regions are typically irregular because of the differences in foundation levels and varying column heights at the ground floor level. Such irregularity triggers the seismic vulnerabilities of buildings on slopes. Enhancing seismic performance by jacketing is a helpful option to reduce vulnerability. Such applications are noted for regular buildings on flat ground. In the present study, an attempt has been made to investigate the possible improvement of seismic performances of reinforced concrete (RC) building frames resting on hill slopes using RC and steel jacketing systems. A typical six-storey, three-bay RC building frame resting on different slopes and strengthened with jacketing systems is considered to explore the effectiveness of such jacketing systems. For this, nonlinear static pushover and nonlinear time history analysis are conducted. Parameters such as roof displacement, inter-storey drift ratio, ductility, ductility reduction factor, response reduction factor, and seismic fragility are studied to understand the effectiveness of a jacketing system. The study reveals that the seismic performance parameters improved significantly when appropriately strengthened with such jacketing systems.