Self-centering of shape memory alloy fiber reinforced cement mortar members subjected to strong cyclic loading

In addition to ductility of the reinforced concrete, it is desirable to have large recoverable deformations (self-centering ability) under strong cyclic loading conditions. Since steel reinforcement cannot regain its shape beyond yielding, the performance deteriorates enormously when subjected to a strong cyclic load. An alternative reinforcement material such as shape memory alloy (SMA) could offer scope for self-centering, thus improving performance especially after a severe loading has occurred. In this study, the load-deformation characteristics of SMA fiber reinforced cement mortar beams under cyclic loading were investigated to assess the self-centering mechanism. The study involves experiments on a beam structure and related analysis for the prediction of self-centering. Apart from the energy dissipation through its ductility, it is shown in this study that shape memory alloy reinforced cement mortar has very good self-centering properties that may be crucial in bringing back the functionality of a structure and prevention of permanent secondary deformations that may lead to catastrophic failure in some structures. © 2012 RILEM.