Seismic performance improvement of base-isolated liquid storage tank based on positive and negative stiffness under different definitions of ground motion duration

As one of the three important characteristics of ground motion, the impact of ground motion duration on the dynamic responses of structures necessitates further in-depth research. Seven different definitions of ground motion duration are selected. The three-dimensional numerical calculation models of non-damping liquid storage tank (LST), rubber-isolated LST, isolated LST based on positive and negative stiffness in parallel, and isolated LST based on positive and negative stiffness in series-parallel are established by ADINA, and the dynamic responses of the different LSTs under earthquakes with different definitions of ground motion duration are comparatively studied. The results show that the influence of different definitions of ground motion duration on the dynamic responses of LST can not be neglected. The dynamic responses are larger under the long-duration ground motion compared to the short-duration ground motions, besides, and the three types of isolation exhibit better performance under long-duration ground motions than under short-duration ground motions. The damping effect of the positive and negative stiffness in series-parallel is the best. The rubber isolation has an amplifying effect on the liquid sloshing wave height, while the isolated system with negative stiffness can make up for this deficiency. Reasonable arrangement of negative stiffness device in isolation layer of LST is helpful to realize dual control of structure responses and liquid sloshing wave height.