Impact of ground motion duration on concrete shear walls reinforced with different types of shape memory alloy rebars

Abstract

The impact of ground motion duration often arises when investigating buildings’ performance in regions susceptible to strong earthquakes, where reinforced concrete (RC) shear walls are typically used as a lateral force-resisting system. Although the seismic performance of these reinforced walls has been improved by the use of self-centering devices and materials, the influence of ground motion duration on self-centering RC walls is not yet well understood. This paper, therefore, examines the effect of ground motion duration on seismic performance and the damage scheme of the self-centering shear wall reinforced with three different types of superelastic shape memory alloy (SE-SMA) in the plastic hinge. A ten-story case study building was analyzed and designed according to the current ASCE 7-16 and ACI-318 practice codes. The maximum inter-story drift ratios (IDR), residual drift ratios (RIDR), shear forces, bending moments, material damages, and collapse margin ratios were examined. The results indicate that IDR and RIDR significantly increased as ground motion duration increased. Meanwhile, the shear forces increased by about 24% on average, which induced only a 6% increase in the bending moments. It was also observed that ground motion duration significantly influenced the scaling factor required to reach the collapse level. Among the examined SE-SMA RC walls, the results indicate that Cu-based SMA RC wall exhibits superior performance in terms of IDR, RIDR, shear forces, and bending moments and performs fairly well in terms of material damage and collapse margin ratio compared to other SMA RC walls. Thus, using Cu-based SMA material in seismically active regions prone to short and long duration ground motions is generally recommended.