Shake table test and identification of RC frame with shape memory alloy bracings

In this study, high seismic performance RC frames have been proposed to have Shape Memory Alloy (SMA) bars acting as a kind of structural bracing system of a frame to increase the energy dissipation capacity. The results of the shake table tests and numerical simulations on a single-bay single-story RC frame with SMA bars are presented. The height and span of the designed frame are 2.0 m and 2.3 m, respectively. The SMA bars are provided in the directions of 40 degrees to the horizontal as bracing. The type of SMA bar used in the study is the Superelastic Nitinol SMA bar. The force-displacement hysteretic loops of the RC frame with SMA bars under seismic loading are presented and compared with the test results of the bare frame. Test results show that the SMA bars can effectively reduce the maximum story drift of the RC frame. It was found that the reduction of story drift and base shear was depending on the characteristic of the input ground motion. Finally, mathematical model for frame with SMA has also been proposed in this study, the related coefficients were regressed in time domain by the least-squared method considering all nonlinear elements.