Nonlinear analysis of reinforced concrete elevated water tanks under various interactions with computer software to be created

Reinforced concrete elevated water tanks are used to store water in areas where the pressure in the water distribution network is insufficient. The main objective of this study is to develop a software to study the dynamic behavior of a reinforced concrete elevated water tank under earthquake ground motion considering various fluid-structure interaction systems. During the modeling of the fluid-structure interaction, the Westergaard approach and the Smoothed Particle Hydrodynamics (SPH) approach are used to model the fluid. Nonlinear modeling of the liquid in the tank was performed with the SPH method. The time dependent hydrodynamic pressures for half and full tanks were obtained with this method. The obtained hydrodynamic pressures were applied to the inside of the wall as an external force. In the Westergaard approach, mass is added to the tank walls for the half and full cases. With the software developed in MATLAB programming language, the structural system of the tank was modeled using the MATLAB PDE toolbox based on the Finite Element method. Dynamic condensation was performed to realize the time-dependent solutions of the mathematical models. The equation of motion is organized in state-space form and the time-dependent solutions of the partial differential equations are solved using ODE45 functions based on the Runge-Kutta method. Both the validation of the developed software and the validation of the finite element model were performed. Using the Westergaard approach and SPH method, linear and nonlinear analyses were performed in time domain for a total of ten models considering empty, semi-filled and fully filled conditions of the warehouse and the analysis results were compared. As a result, in this thesis, the linear and nonlinear analyses of reinforced concrete water tanks in time domain under earthquake ground motions were performed in a short time on personal computers with the software developed. It is seen that if the fluid-structure interaction system and the nonlinear analysis are selected in accordance with the actual behavior, the displacements, deformations and stresses are determined more realistically and are much reduced. Keywords: Nonlinear sloshing, Smoothed particle hydrodynamics method, Elevated water tank, Finite element method, Time history analysis