Seismic Response Analysis Of Story Isolation Structure Based On Modified SMA-Triple Friction Pendulum Bearing

Earthquake can cause shaking of the earth's surface violently,disasters triggered by the earthquake are mainly building damage,landslides,etc.,these phenomena can cause serious disaster.A large number of engineering practices can prove that seismic effect of traditional structure is not obvious.Along with this,the theory of isolation began to sprout,and the vibration control technology was proposed in civil engineering.One of the more mature seismic isolation bearings is friction pendulum bearing(FPB),which provides the reset capability by the tangential component force generated by the vertical pressure.But it may be difficult for the bearing to reset when generating large displacement under strong earthquake.In this paper,the super elastic properties of shape memory alloy(SMA)and the high damping characteristics of SMA spring were considered,and the modified SMA-triple friction pendulum bearing was put forward to form a new type of isolator based on the triple friction pendulum bearing(TFPB).The main research contents include following several aspects:(1)The mechanical principle of the modified SMA-triple friction pendulum bearing was simply analyzed according to the balance of force,and the dynamic response equation of the seismic isolation structure was established.(2)The working principle of the single spherical friction pendulum bearing(FPB)was introduced simply.And the mechanical properties test was carried out,which focuses on frictional coefficient and hysteretic properties.Some key parameters,such as horizontal sliding velocity,vertical pressure,which have influence on the frictional coefficient and hysteretic properties were studied.The hysteresis performance was analyzed by finite element software ANSYS,and the hysteresis curves obtained by numerical simulation,theoretical analysis have agree well with the experimental results,the applicability of the existing bearing model is verified.And the hysteresis curve have stable hysteretic characteristic and enough energy dissipation capacity.(3)The modified SMA-triple friction pendulum bearing(SMA-TFPB)was applied to story isolation of single tower frame structure with a large po dium,and the three models of non-isolation structure,story isolation structure with TFPB and story isolation structure with SMA-TFPB were established.The modal analysis and dynamic time history analysis of the three structures were carried out.It shows that the story isolation structure with modified SMA-triple friction pendulum bearing can improve the damping effect of the structure,and the maximum slip and the residual displacement of the bearing are smaller.(4)The relative acceleration of the lower floors of the isolation layer is "rebounded" when the modified SMA-triple friction pendulum is only set.The story isolation and energy dissipation technology were reasonably combined and applied to the single tower frame structure with a large podium,meanwhile the double-isolation structure was established.The results show that the combined isolation structure can eliminate the phenomenon and has excellent performance of seismic isolation and energy dissipation.