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Evaluation of Seismic Response Parameters in On-Grade Cylindrical Steel Storage Tanks Considering Wave Propagation in Under Laying Soil

Rezaei, Mohamad Hadi | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44906 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Rahimzadeh Rofooei, Fayaz
  7. Abstract:
  8. The circular flexible cylindrical liquid tanks are usually made of steel or aluminum and in majority of cases are built on grade due to its economic advantages. The most important part of a safe design of storage tanks is the accurate estimation of the seismically induced lateral forces that should be transformed to its base through the tank shell and its support . seismic behavior of the liquid storage tank is quite different from regular buildings industrial structures due to its nonlinear behavior caused by complex distribution of hydrodynamic pressure, buckling of its wall, etc.. moreover, the effect of rocking motion caused by under laying soft soil, on its response parameter could be considerable. It should be noticed that arriving to an exact theoretical solution for the response of these tanks could be difficult due to the effect of various parameter such as, soil-structure and liquid-structure interaction, large amplitude nonlinear sloshing, material yielding, plastic rotation of base plate and buckling of tank shell. Therefore, the numerical methods such as finite element methods have been used for their analysis since they offer a concise way of accurately considering all the aforementioned behaviors. Numerous studies have analyzed and investigated the dynamic behavior of fluid storage tanks; however, in most of these studies, it is assumed that the tank is located on a rigid ground. Thus, the effect of soil-foundation system on the dynamic behavior of the tank has not been taken into account. The main object of this thesis was to evaluate the seismic performance of tanks considering fluid-structure-soil interaction and to investigate of different parameter witch has influence on their dynamic behavior. Three earthquake record witch were applied simultaneously in three orthogonal directions and four different soil type of the under laying soil were consider in this study. The fluid-structure interaction was taken into account using ALE fluid FE approximation provide in general purpose program, (ANSYS). Finite element model with absorbing boundary was used to include soil-structure interaction effects. All the analyses were reported for a different height of liquid for evaluating effect of this parameter on the response. It is found that the soil underlying the storage tank has a great influence on the behavior of the tank during the earthquake event such as increasing dynamic pressure with the softening of the under laying soil
  9. Keywords:
  10. Absorbing Boundary ; Flexible Storage Tanks ; Fluid-Structure Interaction ; Soil-Structure Interaction ; Cylindrical Steel Tanks

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