Seismic control of concrete shear wall using shape memory alloys

Abstract

Shape memory alloy is a new functional material, which has found increasing applications in many engineering areas. Research efforts have been extended to use shape memory alloy in controlling civil structures. In this article, both pseudoelastic and shape memory effect properties of Nitinol shape memory alloy are implemented for control of concrete shear wall structure when subjected to seismic excitation. First, the behavior of the concrete shear walls equipped with shape memory reinforcements in its pseudoelastic characteristics is assessed, and the results are compared with the behavior of the ordinary concrete shear wall utilizing steel reinforcements. A finite element time history analysis is employed, and the results indicate that the proposed enhancement of the concrete shear wall with shape memory alloy reinforcements is able to reduce the permanent residual strain in the structure and hence attain reasonable improvement in seismic response. Then, the memory effect characteristics of shape memory alloys by imposing pretension in SMA rebar in concrete shear wall are evaluated. The results show that the concrete shear wall equipped with pretension rebars is much stiffer than either the concrete shear wall equipped with pseudoelastic shape memory alloy rebars or the ordinary concrete shear wall with steel.