Nonlinear simulation of reinforced concrete beams retrofitted by near-surface mounted iron-based shape memory alloys

Retrofitting of reinforced concrete members by near-surface-mounted (NSM) reinforcement is increasingly being investigated as an alternative strengthening method. Applying prestressing with the NSM technique enhances the load carrying capacity during service and results in better utilization of the strengthening material potentialities. Iron-based shape memory alloys (Fe-SMAs) are a cost-effective type of shape memory alloys and can be easily prestressed and used as NSM reinforcements. In this study, strengthening of RC beams in flexure with NSM Fe-SMA reinforcements is explored by developing a 3D nonlinear finite element model in ABAQUS. Comparison between the finite element (FE) model results and experiments in the literature confirms the accuracy of the proposed models. The validated FE model is then used to identify the effects of various design parameters on the performance of RC members strengthened with Fe-SMA reinforcements. Finally, an RC beam strengthened with NSM CFRP strip is modeled and compared to the NSM Fe-SMA strengthened RC beam. It is shown that ductility and energy absorption of the CFRP strengthened beam is significantly less than the Fe-SMA strengthened beam.