## 4 Results and Discussions
### Analysis of Bending Behavior of RC Beams with Different Number of SMA Bars  
In this section, the bending behaviors of the RC beams prestressed with different numbers of the Fe-SMA bars were analyzed with the developed FE simulation models and the results are compared with the experiments. The RC beams considered in this section are the beams prestressed by 4, 3 and 2 Fe-SMA bars. The details of the RC beams considered in this section have been described in Section 2. The geometries and FE meshes of the FE simulation model used in Sections 4.1 and 4.2 are slightly modified according to the real geometries used in the experiment described in Section 2, and used for the FE simulations. The experimentally determined bending load-deflection curves of the RC beams prestressed by different numbers of Fe-SMA bars are shown in Figure 11. In the figures, the bending load-deflection curves of the same RC beams but without Fe-SMA activation are also shown for comparison. It can be clearly seen that the activation of the Fe-SMA bars can effectively produce prestresses in the RC beams. The resistances to the bending deformations of the RC beams increased significantly with the activations of the Fe-SMA bars, regardless of the number of Fe-SMA bars used. The prestressed RC beams showed much higher initial crack loads than the same beams without the activation, as shown in Figure 11b. Figure 12a shows the bending load-deflection curves predicted by the FE simulations for the RC beams with various numbers of activated Fe-SMA bars. The corresponding load-deflection curves obtained by the experiments are shown in Figure 12b for comparison. Although some oscillations occurred in the load-deflection curves obtained by the FE simulations due to the inhomogeneous and localized cracking in the discretized FE elements for the concrete, the overall tendencies of the FE simulation results are very similar to those observed in the experiments. In Figure 12a, the curves move upward without significant  
Figure 10: Comparison of experimental results and FE simulations for bending load-deflection responses of RC beams with 5 SMA bars, activated sequentially and at once. change in slope with an increasing number of Fe-SMA bars, in the FE simulations. The experimentally obtained load-deflection curves showed the same tendency, as shown in Figure 12b. This means that the developed FE model is able to qualitatively represent the bending behavior of the RC beams prestressed by different numbers of the Fe-SMA bars. Therefore, the developed FE model can be used for an optimization study to select the best possible design parameters for prestressing the RC beam with the Fe-SMA bars. On the other hand, the FE simulations slightly overestimate the load response of the RC beams by 20-30 kN for every case. This is probably due to the imperfect bonding between the Fe-SMA bars and the concretes in the real experiments, which was not considered in the FE simulations of this study, as has been discussed in Section 4.1. In Table 1, the RC beam cambers due to the activations of the Fe-SMA bars measured by the experiments [31] are compared with the predicted cambers by the FE simulations. In  
Figure 11: Experimental bending load-deflection curves of RC beams with various numbers of Fe-SMA bars, with and without Fe-SMA activation. (**a**) Overall load-deflection curves up to fracture and (**b**) enlarged view in deflection range of 0–10 mm. Figure 12: Bending load-deflection curves of RC beams with various numbers of Fe-SMA bars with activation, (**a**) predicted by FE simulations and (**b**) by experiments. the case of the RC beam with 5 Fe-SMA bars, it was found that the effect of the sequence of the Fe-SMA activations on the camber of the RC beam is found to be negligible as the FE models with the sequential activation and with the activation at once produced the same cambers of 0.423 mm.