Earthquake Response Analysis Of The Vertical Storage Tank With New Type Structure

The damage of vertical storage tank under earthquake will cause the significant economic loss. Especially the leak of flammable explosive medium, may causes the secondary disaster, which can lead to the serious destroy to the survival environment. Along with the development of oil industry, it is becoming an important research topic to reduce the storage tank seismic disaster. Base isolation, which belongs to the structure control domain, is an effective method to reduce the seismic damage; it reduces the superstructure earthquake damage by means of absorbing the earthquake energy by isolation layers. A new method of the seismic design to tanks is established by means of the base isolation.A comprehensive research about the flexible base isolation tank is contained in this paper, such as the theoretical analysis, digital simulation analysis, experimental study, as well as the seismic tank engineering design method, in order to apply in engineering. Contents and achievements:(1) According to the flexible base isolation tank mathematical model, the storage tank base shearing force and the base moment analysis formulas are revealed by solving the hydrodynamic pressure under earthquake, established the three centralized particles mechanics analysis model.(2) Applying the time history analysis method and the finite element method, the control effect of series base isolation tanks is studied, analyses the influence of isolation parameters. ForⅠ,Ⅱkind locations, the reasonable isolation frequency band isω=2~4rad/s;forⅢ,Ⅳkind locations, the reasonable frequency isω=2~3rad/s, the appropriate isolation damping ratio isξ=0.1~0.3. The isolation storage tank base moment is possible fall to 5%~15% under ideal isolation parameters condition.(3) Shaking table tests of seismic to the flexible base isolation tank are presented. Response to different seismic waves of base isolation tank, such as power frequency spectrum changes and the acceleration is analyzed. The test result indicated that, isolating base might effectively reduce the seismic response of storage tank; it also confirms the accuracy of theoretical analysis and digital simulation.(4) The research on flexible base isolation tank engineering design method is carried on. The isolation tank essential design method and the steps based on double parameters are given, some design variable such as sloshing rigidity, fluid-solid coupling vibration rigidity, and damping ratio are discussed. In addition, the response spectrum design method is presented, and it is applied to analyses the seismic response of storage tank.(5) Considering the design of storage tank experiment model, the structural design method and the specification is given, including the storage tank structural design, the foundation type selecting and design, as well as isolation layers design technical request. It provides a basis design principle for the engineering apply of flexible base isolation tank.