The influence of concrete stress-strain diagram shape on the calculation results of reinforced concrete beams

The level of complexity of design solutions developed for modern buildings for industrial and civil purposes requires flexible and easy-to-use calculation tools that make it possible to describe the stress-strain state of structural elements at various stages of loading as closely as possible. Such an opportunity is provided by calculations based on the application of a deformation model. This method makes it possible to calculate cross-sections of arbitrary shape with different distribution of reinforcement, take into account the peculiarities of the work of materials in different operating conditions or different types of loading, take into account the change in concrete properties due to the use of indirect reinforcement or fiber reinforcement, etc. In such calculations, the most important task is to select the stress-strain diagram that most accurately describes the features of the material’s operation under the accepted conditions. This method also provides a unified approach to determining the bearing capacity and deformations of an element. In this regard, it is necessary to understand to what extent the shape of the selected diagram affects the results of calculations of the bearing capacity and the magnitude of the calculated deformations. But there is a need to understand how much the shape of the selected diagram affects the results of calculations of the bearing capacity and the value of the calculated deformations. In this study, calculations of reinforced concrete beams with various design parameters were performed. The height of the section and the coefficient of reinforcement were varied. For all the samples considered, the calculations were carried out assuming various forms of the stress-strain diagram for concrete: curvilinear, three-linear and bi-linear. The difference in the results of calculations of the bearing capacity and curvature of the element is presented.