Порівняльний аналіз несучої здатності дослідних пошкоджених залізобетонних елементів, підсилених металевими обоймами

Abstract

The paper presents research results and a comparative analysis of the load-bearing deformability and crack resistance of basalt concrete beams brought to the limit state (ULS) in previous tests. The beams were reinforced with prestressed metal clips under high-level static and low-cycle alternating loads. The work performed comparative calculations of reinforced building structures using proprietary methods and existing regulatory methods. A comparison of the experimental and calculated values of the bearing capacity of damaged experimental beam samples showed their unsatisfactory convergence because the well-known regulatory and proprietary methods provide for the calculation of the bearing capacity of damaged reinforced concrete structures along a dangerous inclined crack under the predominant action of transverse force, i.e. the top of a dangerous inclined crack and clamps and vertical elements of external reinforcement. However, experimental and theoretical studies have shown that the destruction of prototype beams with large and medium shear spans under a variable low-cycle load occurs along dangerous inclined through cracks, from the overwhelming action of bending moments, in the longitudinal reinforcement elements of the frame, in the longitudinal tensile reinforcement, as well as transverse beam beams and yield stress cages. That is, the real physical picture of the operation of the system “damaged reinforced concrete beam – prestressed metal reinforcement cage” under alternating transverse load at high levels differs significantly from the physical model of previously existing regulatory and proprietary methods. All existing regulatory and proprietary methods provide for the calculation of the bearing capacity of damaged reinforced concrete structures along a dangerous inclined crack under the predominant action of transverse force, that is, the components of the bearing capacity of inclined sections on concrete above the top of a dangerous inclined crack and clamps and external elements are taken into account. Experimental and theoretical studies have shown that the destruction of prototype beams with large and medium shear spans, under alternating low-cycle loads, occurs along dangerous inclined through cracks from the overwhelming action of bending moments in the longitudinal tensile reinforcement, as well as in the transverse rods of the beam and the cage yield strength.