RC Beams with an Middle Phase of Reinforcement Damage

Abstract This article presents the results of tests of real-size reinforced concrete beams with damaged A500C class reinforcement from 20 to 18 mm in diameter. To achieve this goal, 4 reinforced concrete beams with dimensions of 2100x180x140 mm were manufactured, two of them were control beams and two beams with damaged working fittings from 20 to 18 mm in diameter. The microhardness of the reinforcement with a diameter of 20 mm of class A500C was previously determined and it was established that the outer layer of the reinforcement is thermally strengthened. For heat-strengthened reinforcement, there is a weakening of the physical and mechanical characteristics over time, since corrosion of the surface strengthened layer can occur, as well as local weakening occurs in places of welding, which can be a source of damage formation and changes in the stress-strain state in this section. To establish the real stress-strain state of the reinforcement, tests were conducted on rods with an initial diameter of 20 mm and damaged from 20 to 18 mm, and a decrease in the physical and mechanical characteristics of the reinforcement was established. The next stage of the research was the testing of control and damaged reinforced concrete beams. As a result of the tests, it was established that the reduction of the bearing capacity occurs not only due to the reduction of the cross-section and, accordingly, the cross-sectional area of the working reinforcement, but also due to the reduction of the physical and mechanical characteristics of the reinforcement. it was found that reducing the transverse diameter of the reinforcement reduces the moment when the reinforcement flow is reached by 43%, and the moment when the most compressed concrete fiber is reached by 36%.