This study presents a new way to improve masonry wall behavior. Masonry structures comprise a significant part of the world’s structures. These structures are very vulnerable to earthquakes, and their performances need to be improved. One way to enhance the performances of such types of structures is the use of post-tensioning reinforcements. In the current study, the effects of shape memory alloy as post-tensioning reinforcements on originally unreinforced masonry walls were investigated using finite element simulations in Abaqus. The developed models were validated based on experimental results in the literature. Iron-based shape memory alloy strips were installed on masonry walls by three different configurations, namely in cross or vertical forms. Seven macroscopic masonry walls were modeled in Abaqus software and were subjected to cyclic loading protocol. Parameters such as stiffness, strength, durability, and energy dissipation of these models were then compared. According to the results, the Fe-based strips increased the strength, stiffness, and energy dissipation capacity. So that in the vertical-strip walls, the stiffness increases by 98.1%, and in the cross-strip model's position, the stiffness increases by 127.9%. In the vertical-strip model, the maximum resistance is equal to 108 kN, while in the end cycle, this number is reduced by almost half and reaches 40 kN, in the cross-strip model, the maximum resistance is equal to 104 kN, and in the final cycle, this number decreases by only 13.5% and reaches 90 kN. The scattering of Fe-based strips plays an important role in energy dissipation. Based on the observed behaviors, the greater the scattering, the higher the energy dissipation. The increase was more visible in the walls with the configuration of the crossed Fe-based strips.

The use of shape memory alloys as a rebar in concrete structures has been receiving increasing attention among researchers. In this study, it is intended to evaluate the application of superelastic Nitinol in reducing the damage to the coupling beams and opening corners within a concrete shear wall. Abaqus finite element software was utilized to develop three verified coupled shear wall models. First, a model without diagonal and shape memory alloy rebars is developed to assess conventional shear walls with openings. Steel diagonal rebars are embedded in the coupling beams of the second model, and shape memory alloy diagonal rebars are embedded in the coupling beams of the third model. Shape memory alloy is also implemented in the opening corners of the third model. All models are subjected to cyclic loading to evaluate the concrete damage. Results indicated that the diagonal rebars reduced damage to the coupling beam and opening corners. The damages were the least when shape memory alloy diagonal rebars are utilized in the model. The superelastic behavior of the shape memory alloy also reduced permanent displacement of the shear wall subjected to substantial lateral loadings.

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The use of shape memory alloys (SMAs) has been receiving increasing attention among researchers due to their special properties. One of the most important features of SMA is the superelastic behavior which causes the alloy to be able to remove all the applied deformation. This study is intended to evaluate the application of superelastic Nitinol in knee braced steel frames (KBF) as a damper. To fulfill the objective of this research, an experimental KBF system has been developed in ABAQUS using the microscopic finite-element method (FEM). The proposed superelastic damper is placed between the knee element and beam-column connection. Five SMA dampers with different stiffness are located in the KBF system and subjected to static cyclic loading. The hysteresis diagram obtained from this cyclic loading indicates that the damper increases the system strength. The greater the stiffness of the SMA damper, the higher the strength is. Furthermore, the superelastic alloy reduces the permanent deformation and the dissipation energy capacity of the KBF system. Totally, the SMA-equipped KBF system indicates a little lower energy dissipation capacity compared to the KBF system. However, based on the hysteresis diagrams, the reduction of residual deformation in all models is significant compared to the little reduction in energy dissipation. Therefore, the proposed SMA damper is capable of reducing the permanent deformation of the KBF system and maintaining the energy dissipation capacity at almost the same level, which is essential for keeping the structure stable.