IntroductionThe use of steel fibre-reinforced concrete for foundations or industrial floors is a typical example. In these cases, the design encompasses many input parameters that significantly influence the results. The basic requirements to optimize the design include in particular a detailed understanding of the properties of the materials used. This is especially important in the case of complex design situations and the use of advanced numerical simulations. In these cases, it is necessary to describe the material properties in a comprehensive manner. A typical case is fibre-reinforced concrete. Fibre-reinforced concrete exists in a number of variants which differ in the materials used and the shape of fibres [20]. Common problems include the fact that experimental programmes and testing focus on the properties and testing of the selected material [21]. This hinders the creation of advanced material models for the numerical simulation of the actual behaviour. This is especially the case of nonlinear analysis and the finite element method which requires a detailed computing model and a more comprehensive description of the actual material behaviour. During plane and space problems, a general state of stress emerges. It is also necessary to describe and model the damaged material. This is used to describe concrete fracture mechanics [22]. The juxtaposition of specialized tests often creates questions, thus comprising the research space for a more comprehensive description of the material properties.With regard to the research project and the goal of a comprehensive description of the material properties of steel

Abstract:The article handles potential approaches to design and determination of total load capacity of foundation slabs and floors. The research is focused on punching shear failure of reinforced ground supported slab. The article presents detailed results of the experiment made and advanced numerical modelling based on nonlinear analysis and application of fracture-plastic model. The experiment made included a 2.0 9 1.95 m reinforced concrete slab-on-ground of 120 mm thickness. The experiment was followed by a parametric study of total load capacity calculation with nonlinear analysis which is supplemented by calculations based on existing design model code.

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The goal of the paper is to model and evaluate the total load capacity of the reinforced concrete beams. A non-linear analysis and finite element method were used for that purpose. The model consists of 3D finite elements. The constitutive model of concrete for the non-linear analysis is based on a fracture-plastic theory. The input parameters are the data obtained in previous tests which included both standard tests and additional tests of the testing bodies. There is no shear reinforcement in the beams. The non-linear calculations were carried out for several variants. The study takes into considerations the influence of concrete properties as well as the size of the finite elements.

The purpose of this paper is to compare calculation of internal forces and deformations of slabs for two calculation methods: the finite element method and the finite difference method. Two concrete slabs have been analysed. In the case of the finite element method, different element mesh are used, providing, thus, solutions in different variants. The calculation and algorithms is based on a thin slab theory. Variants calculate in program Scia Engineer effects of shearing forces by means of the Midlins theory or thin slab theory. Algorithms for the calculation were developed in Matlab.