Evaluation of Seismic Response of Concrete Structures Reinforced by Shape Memory Alloys

Shape memory alloys (SMAs) are unique smart materials that have many advantages, such as ability to resist large strains without leaving residual strains and ability to recover original form. However, the high costs of SMAs have limited their usage. This paper evaluates the behavior of concrete structures equipped with SMAs in an optimal manner as they are being used along with plastic hinge of the beams. For this purpose, a reinforced concrete (RC) beam, a 2D RC frame and a 3D RC building were considered, which were tested in previous studies under cyclic loading and on a shaking table. After verifying RC beam in the Seismostruct software, the steel rebars are replaced by SMAs in all connections of models and time history analysis is performed. The seismic response of concrete structures equipped with SMAs is compared with the conventional RC structures. The maximum base shear and roof displacement, amount of residual displacement and distribution of interstory drift at the structure height are among the factors to be evaluated. The results showed that, due to the use of SMAs in concrete structures, the maximum base shear did not significantly change compared with the conventional RC structures, and the residual displacements in the structure roof have been reduced. On the other hand, the maximum displacement of the roof was increased in the structures with SMAs. The concrete structures equipped with SMAs experience a slight residual deformation, and the distribution of interstory drift is even more uniform at the height of such structures.