Seismic performance of vertex-rotation type self-centering link beam equipped with SMA bars

Abstract

This paper presented the seismic performance of self-centering energy-dissipating link beams that rotate around the vertex. The effects of the connection types of NiTi shape memory alloy (SMA) bar and the material of energy-dissipating steel angle on the self-centering performance, energy-dissipation capacity, bearing capacity, ductility, rotation mode, and strain distribution of link beams were explored through tests. It was verified through theoretical calculation and finite element analysis method, and the specimens were improved in design. The results show that the self-centering link beams have typical flag-shaped hysteretic curves and have excellent self-resetting performances and energy dissipation capabilities. Plastic deformations were concentrated on the steel angles. LY160 steel angle can enable the link beam to obtain better self-centering performance, while the Q235 steel angle can improve the energy dissipation capacity. The full-length SMA bars link beam has better self-centering performance and energy dissipation capacity than the partition SMA bars link beam. The theoretical calculation and finite element analysis results are consistent with the testing results. The self-centering performances of the improved design specimens were improved, but the energy consumption capacities were slightly reduced. The steel angles of the self-centering link beam after an earthquake are easy to replace and can quickly restore the structural function, which effectively solves the post-earthquake large residual deformation and difficulty of repair of traditional link beam.