The paper presents the results of an experimental investigation of statically determinable pre-stressed concrete beams with tension on concrete (using post-tension). The authors consider the existing practice of applying post-tension in reinforced concrete structures, the current regulatory documents of the Russian Federation containing information on the strength and deformation properties of post-tension. The paper contains information about the loading pattern, beam-fixing conditions, geometric characteristics of a reinforced concrete beam, physical characteristics of concrete and reinforcement of an experimental sample, technical characteristics of pre-stressed reinforcement. The authors present the research results using graphs of structural deflection changes under load, the distribution of relative strain along the depth of a concrete cross-section, as well as cracking and failure schemes of experimental samples. The research presented in the paper showed that the destruction of the samples occurred along a standard cross-section and was brittle. As a result of processing the results of experimental data, loads of crack formation and critical crack width were determined. The authors confirmed the effect of pre-stressing on crack resistance and the magnitude of the deflection of bent reinforced concrete elements.

The article presents the analysis of the stress state of a flat reinforced concrete slab under punching through a numerical study on finite element models. Three models with different cross – section shape of the column-square, rectangular and L-shaped-are considered. The calculation of the punching according to the standard method is carried out under the assumption of a uniform distribution of shear stresses on the control perimeter of the punching. The results of the study allow drawing a conclusion about a significant uneven distribution of shear stresses on the control perimeter, depending on the shape of the cross-section of the column. The conclusion corresponds to the results of previously performed experimental studies on test samples. According to the results of the study, the effective length of the control perimeter of the plate punching for the considered forms of the column cross-section is determined.