Experimental study on self-centering link beams using post-tensioned steel-SMA composite tendons

Abstract Compared with conventional steel link beams, which undergo unrecoverable plastic deformation during earthquake, the self-centering link beams exhibit recoverable deformation under seismic load. This paper illustrates a new concept of self-centering link beam system which uses post-tensioned composite tendons consisting of steel rods and shape memory alloy rods to provide re-centering force and energy dissipation capacity. A pseudo-static experiment was conducted to testify the feasibility of this novel self-centering system. The experimental results showed that the self-centering link beam system using composite tendons was able to re-center from the designed rotation of 8% rad with a negligible residual deformation and a medium energy dissipation capacity, and possessed an over-strength factor comparable to conventional systems. A numerical simulation on the experiment was carried out to cross-validate the experimental results. Comparison between the numerical results and experimental results showed they were generally consistent with each other.