Parametric Study of RC Jacketing on Seismic Vulnerability of Non-ductile RC Frame Building

Non-ductile Reinforced Concrete (RC) frame buildings in urban areas where older structures were constructed using outdated design practices have less seismic resistant capacity. Based on current safety measures, these buildings show inadequacy in reinforcement and insufficiency in strength of concrete. To address these problems, retrofitting and strengthening measures must be implemented to improve their seismic performance. The primary objective of this study is to examine the vulnerability of a retrofitted RC frame by RC jacketing. A finite element (FE) modelling of a 3-storey 3-bay RC frame building has been modelled using finite element software OpenSees. Non-linear static analysis has been performed to compare the performance of the frame before and after retrofitting. Non-linear time history analysis (NLTHA) of retrofitted frames has been performed to obtain peak responses with respect to damage states (DSs). The size of the RC jacket has been varied to assess the influence of jacket thickness on the overall performance of building, considering constant reinforcement area. Another parametric study is considered using retrofitting in different storey levels. It has been observed that the damage states corresponding to bare and retrofitted frames are attained at a relatively low and high inter-storey drift ratio (IDR), respectively. This indicates that the retrofitted structure is more likely to achieve a higher performance level than the bare frame. This study demonstrates the potential of RC jacketing as an effective seismic retrofitting technique for RC frames.