Deformation approach to the calculation of compressive strength of steel-reinforced concrete elements

Introduction. Compressed steel-reinforced concrete structures, due to the requirements of reduced cross-sectional dimensions for vertical load-bearing structures with high strength and rigidity of structures, as well as their fire resistance, are widely used throughout the world in the construction of high-rise buildings, entertainment structures, etc. Methods for their calculation are constantly being improved. The deformation approach to calculation makes it possible to obtain the parameters of their stress-strain state (SSS) at any stage of deformation under load, to take into account physical nonlinearity of the materials and the loading stages. Materials and methods. The selection of compressed steel-reinforced concrete elements for the theoretical study was made according to the data published in open sources. A cross-sectional model was compiled, taking into account the joint work of concrete, rigid and flexible reinforcement, and their deformation diagrams, taking into account physical nonlinearity. A criterion for the destruction of the cross section of a steel-reinforced concrete element without limiting the limiting deformations of materials under compression is proposed. Results. The prerequisites for using the deformation approach to the calculation of steel-reinforced concrete elements are formulated. Two stages of their operation are considered: under the action of forced shrinkage deformations during concrete hardening and subsequent loading. Using examples of the accepted specimen of compressed steel-reinforced concrete elements, the advantages of the deformation approach in their calculation are shown. Conclusions. The deformation approach to calculation makes it possible to obtain the SSS parameters of compressed steel-reinforced concrete elements of arbitrary cross-section shape with different distribution of reinforcement over the cross-section, to take into account the nonlinearity of deformation of materials, concrete shrinkage. The proposed criterion for the destruction of compressed steel-reinforced concrete elements allows to take into account the redistribution of forces between concrete, rigid and flexible reinforcement to full extent.