Seismic Performance Investigations Of Steel Frame Structure Based On New Self-Centering SMA-BRB

Shape Memory Alloy(SMA)has attracted attention in civil engineering due to its properties such as superelasticity,and shape memory effects.It is relatively recent that the potential of the SMA based devices are used in conjunction with the dampers and braces.Buckling restrained braced(BRB)has increasingly been employed as seismic loadresisting systems since their ductility,stable hysteretic behavior,and large energy dissipation capacity.While dissipating a considerable amount of energy under cyclic loads,BRBs are still prone to severe damage due to significant residual drifts during strong earthquakes.To improve the performance of traditional BRB and reduce its residual deformation,an innovative self-centering buckling restrained brace(SMA-BRB)was proposed by BRB systems containing SMA cables.The main research contents of this paper include:(1)Presenting an investigation on the effects of strain amplitude,loading frequency,and temperature on the superelastic behavior of SMA.The effects of the loading rate and strain amplitude are more pronounced on the superelastic behavior.Numerical simulation was used to verify the proposed improved SMA constitutive model.Compared with the experimental results,the improved constitutive model can describe the superelastic behavior of SMA more comprehensively.(2)A self-centering buckling restrained brace(SMA-BRB),utilizing self-centering BRB systems containing SMA cables is proposed.The configuration and working principle of the proposed SMA-BRB were described,followed by theoretical studies on hysteretic models.Numerical simulations were carried out to investigate the mechanical performance of the proposed SMA-BRB.(3)Analyzed under different seismic action based on the SMA-BRB response of steel framework structure and energy consumption,it was discovered that the configuration of the SMA-BRB can effectively reduce the structural response,and the energy consumption accounts for a large part of the total seismic energy.The SMA-BRB can stably provide the supporting force of the main structure,the residual displacement of the brace is weeny and ensure stable self-centering performance.