The aim of this article is to introduce the results of experimental and theoretical studies on the deformability and crack resistance of damaged concrete beams reinforced with basalt-plastic reinforcement and strengthened with carbon-fiber jackets in the support regions. The paper presents the results of studies of the deformability and crack resistance of basalt-concrete beams, brought to the boundary state (ULS) in previous tests, reinforced with external fiber-reinforced plastic (CFRP). These data are presented in the form of experimental statistical relationships of the main parameters of the performance of the prototypes from design factors and levels of low-cycle repeated load. The greatest influence on the deformability of materials and test samples - damaged basalt concrete beams, reinforced with carbon fiber, have: the value of the relative span of the cut (а/h0), then - the class of concrete (C) and, finally, the coefficient of transverse reinforcement ( ) of their supporting areas. The conducted experimental and theoretical studies confirmed the expediency and possibility of using fiber-reinforced plastics (CFRP) for strengthening external structures damaged by force cracks and brought to limit states according to the first (ULS) and second (SLS) groups of reinforced structures according to the established technology.

No abstract

В статті приведені результати досліджень несучої здатності звичайних (еталонних) і підсилених вуглепластиковим полотном у нижній розтягнутій зоні та на приопорних ділянках пошкоджених бетонних балках з BFRP за дії статичного ступенево зростаючого малоциклового навантаження.

The aim of this article is to familiarize with the experimental and theoretical study of the load-bearing capacity of BFRP concrete beams damaged in previous studies and brought to failure, reinforced with carbon-plastic fabric in the lower stretched zone and carbon-plastic jackets in the supporting areas under the action of low-cycle sign-repeated transverse loading of high levels with the development of initial data for the physical model of the methodology for calculating the strength of their normal and inclined sections. The article presents the results of testing concrete beams reinforced with ВFRP, strengthened with carbon fiber reinforced polymer (CFRP) strips in the lower tensile zones and carbon fiber reinforced polymer jackets at support sections, previously tested to ultimate limit state (ULS). The load-carrying capacity of the reinforced FRP support sections of beam structures, brought to the ultimate limit state (ULS), should be determined primarily under the action of bending moment through the critical inclined crack. The performed experimental and theoretical studies have established the possibility and feasibility of strengthening damaged and brought to the boundary state (ULS) concrete structures with BFRP external fiber-reinforced plastics (CFRP) while observing the established technology. The bearing capacity of CFRP-reinforced damaged concrete beams with BFRP should only be determined for the action of bending moments along normal sections in elements with large (a/d = 3) and medium (a/d = 2) shear spans and along inclined sections in beams with small (a/d=1) shear spans.

Experimental data on strength, deflections and cracking in beams are presented. Beams are made with dimensions 2000x200x100mm with steel and basalt-plastic (BFRP) reinforcement. They have been tested for static and low-cycle reloading. The results of studies of the main parameters of the performance of research elements are presented in the form of the corresponding experimental-statistical dependences for the actions of operational and destructive loads with the same design factors. With the help of stochastic and graphical analysis, the influence of the type of reinforcement and design factors on the strength and deformation characteristics, as well as on the crack resistance of experimental samples - beams, is estimated.