EXPERIMENTAL STUDIES OF THE STRENGTH AND DEFORMABILITY OF THE REGULATED CHEKANOVYCH BEAM

Abstract

The study analyzes reinforced concrete beams known in international construction practice, strengthened with internal and external bars. At the same time, it is noted that in the case of external bars in the beams, the ability to redistribute forces to increase their strength and stiffness is not used effectively enough. The structure of a reinforced concrete beam reinforced with an adjustable system according to the author's Ukrainian patent No. 3112733 was considered. The beam is strengthened by an external transverse-longitudinal system of ties. The system regulates and rationally redistributes stresses and deformations in the beam that strengthen it. To evaluate the effectiveness of the beam reinforcement system, experimental laboratory studies were performed. The specified reinforced beams with force adjustment were manufactured. In addition, conventional beams were made for comparison. For quality control, control concrete samples were also produced. Beam samples and concrete samples were tested in the construction laboratory of the university. According to the results of load tests, the stressed and deformed states of the beams were determined. Beam loading was traditionally carried out in the thirds of the span by two concentrated forces. The load was done with a mechanical jack for the possibility of fixing the deformed state. Based on the results of the tests, graphs of the dependence “bending moment – deflection” and “bending moment – deformation” of the upper and lower fiber of the experimental beam were constructed. The bearing capacity and strength of the beams were determined. As a result of the tests, it was found that the beams strengthened by the regulated system were stronger by almost 40% compared to the conventional reference ones. They were stiffer, had smaller deflections under the same load. The reinforcement system effectively redistributed the forces in the beam. Summarizing, we came to the conclusion that the regulated beam according to Ukrainian patent No. 3112733 can be effective in construction both for new construction and for strengthening existing beams of buildings and structures.