Seismic performance enhancement for low-rise and mid-rise steel frames using novel self-centering beam-to-brace links

This paper aims to propose a novel self-centering beam-to-brace link with examined Shape Memory Alloy (SMA) based apparatuses to improve the seismic resilience of steel frames. Based on the past experimental data, a three-dimensional computer model of the proposed link was established to simulate the nonlinear hysteretic behavior. The results showed that the proposed link could realize the perceived advantages. A simplified Finite Element (FE) model was developed and validated via the comparison with the computer model. A 3-story and a 9-story representative building were rehabilitated with the proposed link. The Nonlinear Response History Analyses (NRHAs) were conducted on the original and rehabilitated systems to evaluate their seismic performance comparatively. To achieve a fair comparison, the original and rehabilitated systems had the proximate vibration periods and the same flexural strength under a roof drift ratio of 2 %. Compared with the original systems, the corresponding rehabilitated systems exhibited equivalent performance of transient inter-story displacement, significant advantages in eliminating residual deformation, and slight disadvantages in limiting floor acceleration. A comprehensive measure was developed and revealed the rehabilitated systems achieved superior seismic overall performance compared to the original systems.