Seismic Response Analysis Of Rectangular RC Liquid Storage Structures

Rectangular RC(reinforced concrete) liquid storage structures, which are broadly used to reserve rinsing, sewaeage, petroleum and chemical liquid, etc., are mainly applied to such corporations as water-supply and drainage, sewerage-disposal, petroleum, chemical industries and so on. Because the influence of the liquids in them, the dynamic characteristics of liquid storage structures are different than other kind of structures. Therefore, this thesis, aiming at the aboveground rectangular RC liquid storage structures, the analytic method, finite element simulation method and modal experiment method are used synthetically to study the vibration considering FSI (fluid-structure interaction) systematically.Firstly, the dymanic finite-element model that includes the effect of fluid-structure interaction for rectangular RC liquid storage structures is established. In this model, the influence factors such as the solution method of nonlinear dynamic equation, the selection of element, the input method of earthquake waves, the mesh density, the convergence of the solution, and the achievement of FSI are all considered.Then the problem of the free vibration characteristics for the rectangular RC liquid storage structures is performed. In accordance with shearing cantilever beam theory, the vibration equation of the rectangular liquid storage structures with liquid-structure interaction is established. After that the 3D finite-element model of frequency domain analysis considering FSI is established. The influence of the surface gravity waves upon the liquids, the depth of the liquids, the stiffness of the wainscots and the shape of the structures on the frequency domain characteristics of liquid storage structures with liquid-structure interaction are discussed respectively.Furthermore, the 3D finite-element model of dynamic analysis for rectangular RC liquid storage structures considering FSI is established. The distribution situation of the stress and strain by the action of various earthquake waves is probed. The influences of the gravity waves upon the liquids surface, the stiffness of the wainscots and the shape of the structures on the dynamic response with liquid-structure interaction are discussed. The dynamic response is also discussed by the action of the unidirectional, bidirectional and three-directional coupling seismic actions.Finally, through the modal experiment and corresponding finite-element analysis of square thin wall liquid storage structures, the influences of the liquids, the top plate, and the relative thickness of the wainscots on the vibration frequence with liquid-structure interaction are discussed. It verifies the validity of the finite-element model and correlative results in this paper.