Investigation of earthquake behaviors of soil-exterior wall of tank-fluid systems

In rectangular tanks, the interactions of exterior walls with fluid, backfill soil and foundation soil convert the earthquake behaviors of these structures into a fairly complex problem. However, when the literature about the structure systems within the scope of the study is investigated, in general, it is seen that there appears a deficiency related to earthquake calculation and design of the exterior walls which interacting with soil and fluid. The main purpose of this study is to propose numerical and analytical approaches for investigating the earthquake behaviors of fluid-exterior wall-soil systems using the approaches proposed in the literature for consideration of fluid and soil interactions, and to investigate the validities and usabilities of the proposed models by means of in-situ modal tests. Furthermore, examining the earthquake behaviors of the said systems via the approaches which appeared to be sufficient, it is also aimed to investigate the effects of both interactions on structure behavior.The study consists of three main chapters and an appendix. In the first chapter, general information about rectangular tanks, dynamic and nonlinear behaviors of soils, soil-structure and fluid-structure interactions, and the aim and scope of this study are presented. In the second chapter, the analytical and numerical models proposed for soil-exterior wall-fluid systems are introduced and information about in-situ modal tests are given. Subsequently, modal characteristics of systems mentioned above are determined by the proposed models and modal tests, and earthquake analyses are fulfilled. In the third chapter, conclusions obtained from the study and suggestions are given. This chapter is followed by references list, autobiography and the appendix.Consequently, in this study, the validities and usabilities of analytical and numerical models via in-situ modal tests were investigated. Furthermore, it was seen that fluid and soil interactions can significantly change the earthquake behaviors of rectangular tanks depending on backfill geometry and/or existence of backfill, embedment shape, height of fluid and the mechanical properties of foundation/soil system.Key Words: Rectangular Tank, Soil-Structure-Fluid Interaction, In-Situ Modal Test, Modal Characteristic, Lagrange Approach, Artificial Boundary, Earthquake Behavior, Finite Elements Method, Substructure Approach