Response comparison of different staggered story isolated structures under long-term earthquake

The staggered story isolated structure is a new type of isolated structure developed from the base isolated structure.It has great isolation performance under ordinary earthquakes.However, the problem of long-term earthquakes exists in many areas. The prolongation of the natural vibration period of the structure and the resonance caused by the low-frequency part of the long-term earthquakes should not be ignored. The research on the response of the staggered story isolated structure under the long-term earthquakes is not perfect.Two finite element models of staggered story isolated structure were established and non-linear time-history response analysis were carried out under ordinary earthquakes and long-term earthquakes,which including near-fault pulse-type long-term earthquakes and far-field harmonic-like long-term earthquakes.Results show that the natural vibration period of the staggered story isolated structure is prolonged,the seismic response is reduced.Under long-term earthquakes,the story drift angle,bearing displacement,story shear,plastic hinges and stress damage of staggered story isolated structure are partly larger than those of ordinary earthquakes.Under the far-field harmonic-like earthquakes,isolation performance is significantly different from those under the near-fault pulse-type earthquakes.And there are significant differences between the two models.The structure has the characteristics of vertically irregular structures and the weak position of the structure is located near the isolation layer,so more attention should be paid to the project.