Influence of Damage in the Compressed Zone of Concrete on the Bearing Capacity Along Inclined Sections and Crack Formation Characteristics

The presented results encompass an analysis of experimental data obtained from determining the bearing capacity of reinforced concrete beams with rectangular cross-sections, featuring damage in the compressed zone of concrete. During the conducted investigation, 15 reinforced concrete beams with dimensions of 100 × 200 × 1200 mm were tested for bearing capacity, exhibiting varying degrees of damage and relative shear span ratios av (within the range of 1d, 2d, and 3d). Statistical processing of the laboratory research results was performed utilizing regression analysis, and based on the obtained results of the ultimate shear force Vu, a three-factor nonlinear experimental-statistical model was constructed. The results indicate that the relative shear span ratio exerts the greatest influence on the ultimate shear force, followed by the angle and height of damage to the element. It was established that as the damaged area increases, the width of crack opening decreases. Furthermore, samples with similar damaged areas but differing ratios of damaged height to damaged angle exhibit varying widths of crack opening. Additionally, it was found that the initial cracks do not form simultaneously from the parallel faces of the element when damage is present near one of the faces; they also exhibit varying widths of crack opening.