Iron-based shape memory alloys for prestressed near-surface mounted strengthening of reinforced concrete beams

In this study, an experimental program was established to investigate the flexural behavior of reinforced concrete (RC) beams that were strengthened and prestressed with Fe-SMA strips. The specific focus was on the demonstration of the feasibility of this strengthening technique. A total of six RC beams were experimentally examined under deflection control in a four-point bending loading rig. The experiments consisted of one beam strengthened by Fe-SMA strips but not prestressed, three beams strengthened by prestressed Fe-SMA strips, and one beam strengthened by one CFRP strip. Additionally, one beam with no strengthening, which served as the reference beam, was examined. The results showed that the cracking loads and mid-span deflections of prestressed beams compared to other beams were, respectively, higher and lower. Significant strengthening effects were achieved in NSM Fe-SMA-strengthened beams compared to the reference beam. These direct effects showed that the application of near-surface mounted Fe-SMA strips worked well as prestressing elements in concrete beams.