ABOUT THE EXPERIMENTAL INVESTIGATION OF RESIDUAL BEARING CAPACITY OF DAMAGED REINFORCED CONCRETE BEAMS INCLINED SECTIONS

Abstract

The article reports on the results of the experimental studies to determine the effect of concrete damages in compressed zone of rectangular cross-section reinforced concrete beams on their residual bearing capacity of inclined sections. The special experimental installation and hydraulic jack-screw were used for the tests. According to the experimental plan, 16 single- span freely supported experimental samples of reinforced concrete beams were tested. All examples had own number from Б0 to Б15 (example Б0 was the twin of example Б1). The acted load on the samples was applied as a concentrated force and was added in uniform steps with an exposure in 10–15 minutes. The dimensions of the beams were 100×200×1200 mm and the working span is 1000 mm. In the beams the artificial damages of the compressed zone of concrete are laid in advance in different sizes with different angles relative to the edge of the beam, and the different size of the shear span с (1d, 2d, and 3d) are also used. Materials used for beams are: concrete ‒ grade C25/30; working longitudinal reinforcement ‒ Ø 18 mm of grade A500C; constructive longitudinal reinforcement and transverse reinforcement in the form of vertical links ‒ Ø 6 mm of grade А240С. According to actual codes the physical-mechanical properties materials were determined on the control samples – cubes, prisms and rebars. All samples were destroyed along an inclined section. It has been established that an increase in the shear span (from 1d to 3d) leads significantly to a decrease in the carrying capacity (especially from 1d to 2d). As well, within the shear span, the appearance of damage and an increase in their size results in a decrease in the carrying capacity of the samples. The experimental data obtained will be used in the development of a method for determining the residual bearing capacity of inclined sections.