Abstract
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.
Highlights
Unreinforced masonry structures comprise a significant part of the world’s existing structures, and some of these structures are even of high cultural and architectural value in their home countries
Damage applied in the form of tensile and compressive to the model reduces the stiffness of the material according to the concrete damage plastic (CDP) model
The Fe-based alloys were installed in the form of crosses and vertical strips in walls, and post-tension stress was applied to them
Summary
Unreinforced masonry structures comprise a significant part of the world’s existing structures, and some of these structures are even of high cultural and architectural value in their home countries. According to Sadeghi’s research, increasing the axial load on the wall can increase its shear strength and decrease its displacement capacity He observed that a high increase in the compressive stress by post-tensioning might change the failure mode to diagonal cracking [12]. Farshchi et al proposed a general analysis tool to predict the in-plane behavior of the masonry walls They investigated the effects of post-tensioning on the lateral response of these walls [17,18]. Their results indicated that the axial force improves strength and decreases lateral ductility They investigated the effect of brick size and mortar on URM walls’ in-plane behavior [19]. Cyclic loading was applied to all models, and their performance was compared with each other
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