Modelování betonových konstrukcí metodou konečných prvků

Abstract

At present time the importance of more accurate determination of reinforced concrete structure bearing capacity is a problem, because it is one of the most important parts to accurately define service life of these structures. A goal of this work is to evaluate and prepare theoretical relationships of the physical non-linear analysis to create a computer program, the verification of the created program using available experiments, and determination of the program limitations. The first chapter describes the area of concrete and reinforced structure analyses and solutions. The second chapter deals with the current capabilities of the static analysis of building constructions and shows approaches that are used for constitutive models. As far as numerical methods are concerned the force method, differential method and finite element methods are described. The methods to solve linear and non-linear equation systems are also mentioned. The constitutive models presented here are elastic-plastic ones, models based on the smeared crack concept, and combined models. The third chapter describes aims of this dissertation. The fourth chapter describes selected solution methods. The deformation version of the finite element method is described here, as well as used finite elements, the conjugate gradient method, the Newton-Rapson method, and the elastic-plastic concrete model that combines the Chen-Chen plasticity condition and the reinforcement model created by Ohtani. The constitutive models of concrete and conditions of failure and plasticity, which were chosen to verify the applicability of created program, are also mentioned. Detailed equations of smeared and discrete reinforcement model are also described here. The slip between concrete and its reinforcement is modeled using special bond element, which is also mentioned in the thesis. The fifth chapter shows the performed numerical analyses of available experiments. The modeled experiments are beam, T-beams and wall ones. Evaluations of constitutive concrete models and the failure and plasticization conditions are described in the annexes. The conclusion includes a summary of achieved results and limitations of the created program. The annexes contain additional information on numerical analyses that were carried out and the created program.