Seismic Behavior of Low-Rise Shear Walls with SMA Bars

Abstract

In recent years, researchers have focused their study on many possible approaches to enhancing the seismic performance of structures. One promising solution which is receiving attention today is the application of Shape Memory Alloys (SMA). In this study, high seismic performance shear walls have been proposed to have SMA bars acting as a kind of structural bracing system at both sides of the shear walls to increase the ductility and the energy dissipation capacity of the low-rise shear walls. This paper presents the results of the reversed cyclic tests on low-rise shear walls with SMA bars. The height, width, and thickness of the designed shear walls were 1.0 m, 2.0 m and 0.12 m, respectively. SMA bars were provided in the directions of 25 degrees to the horizontal (from the top corner to the bottom corner of the wall). The steel ratio in both perpendicular directions of the shear walls was 0.24%. The main parameter used in the study is the type of SMA bars, namely Superelastic and Martensite SMA bars. The force-displacement hysteretic loops of the low-rise shear walls under reversed cyclic loading are presented. Test results show that the maximum shear strengths of the tested walls are affected by SMA bars. It was found that the shear wall with Martensite SMA bars has greater residual displacement. In contrast, the shear wall with Superelastic SMA bars has less residual displacement. At the ultimate state, one of the four Superelastic SMA bars buckled, resulting in less energy dissipation capacity than the expected value. How to prevent the buckling of SMA bars needs to be investigated in the near future.