From experimental strain and crack distributions to plastic hinge lengths of RC walls with SMA rebars

Abstract

Modern-designed reinforced concrete walls can typically achieve the primary performance level of collapse prevention in a moderate-to-large earthquake event. However, the substantial amount of damage sustained by the wall can result in large residual displacements of a building, often requiring costly repairs or even demolition. Localised replacement of reinforcing steel for a pseudoelastic material, such as shape memory alloys, has been offered as a potential solution for reducing residual displacements of reinforced concrete walls. This paper examines two basic assumptions that can be employed for the simulation of reinforced concrete walls with shape memory alloy rebars using distributed and lumped plasticity line models, namely: plane-sections-remain-plane and plastic hinge length. To this purpose, the authors analyse the strain and crack distributions using the experimental data from a recent experimental campaign. Digital image correlation techniques were used to capture the displacement field of the surface of the walls. Experimental findings are presented, including crack distributions and salient crack widths, longitudinal strain profiles along the wall length and height, and curvature profiles. They are used to discuss the validity of the plane-section hypothesis and equivalent plastic hinge length expressions. A conventional wall reinforced with steel rebars is used for comparison purposes. The experimental results presented in this paper are useful for the ongoing international investigations on concrete structures detailed with shape memory alloys.