the article deals with the issues of anchoring external composite reinforcement. The advantages of one of the reinforcement options are described - with the help of anchor harnesses. The procedure for performing work when reinforcing with anchor harnesses is presented. Also presented is a method for calculating pull-out anchors made of carbon fibers.

Keywords: reinforced concrete, concrete, composite materials, carbon fiber, reinforcement, external reinforcement, composite anchor

А comparative analysis of individual indicators of the classical and new methods of strengthening reinforced concrete structures is given, a possible option for increasing the level of efficiency of external composite reinforcement is shown. The elements of the research program are presented, with a description of the materials and the main characteristics of the samples.

Keywords: reinforced concrete, concrete, rebar, composite materials, carbon fiber reinforced plastic, reinforcement, external reinforcement, experiment

Presents the results of a study of the strength of inclined sections of reinforced concrete beams, reinforced with double-sided carbon fiber clamps. An assessment of the effectiveness of composite reinforcement is given when the value of the cut span is changed, which was equal to 1.5h0; 2h0 and 2.5 h0. At the same time, the degree of influence of the initial inclined cracks on the bearing capacity of the inclined section was analyzed.

Keywords: reinforced concrete, beam, reinforcement, composite materials, carbon fiber reinforced plastic, inclined sections, clamps, reinforcement

The strength, deformability and width of the opening of normal cracks of prototypes 220, section 12.5x25 (h) cm, reinforced with composite canvases and laminates of different cross-sectional areas, made on the basis of glass and carbon plastics, are compared. The samples had working reinforcement, represented by 2Ø14А600, transverse - with double-section clamps Ø5В500, installed with a pitch of 100 mm. Samples were loaded with two concentrated forces applied in thirds of the span. With composite reinforcement, the appearance of the external composite reinforcement was varied, as well as the presence or absence of U-shaped anchoring clamps glued to the supporting sections of the beams. It has been established that the greatest reinforcing effect is provided by composite materials based on carbon fibers, in which the modulus of elasticity is comparable to the modulus of elasticity of steel.

Keywords: concrete, reinforced concrete, bending element, composite, fiberglass, carbon fiber, strength, deformability

Comparison of the results of the deformation and stiffness test of flexible compressed reinforced concrete colums strengthening with various variants of external transverse and longitudinal reinforcement by composite materials is given. The influence of the rigidity of the reinforcement elements on the deformation properties of the test samples with a cross section of 250x125 (h) mm is given for the flexibility λh = e0 / h = 20, which were tested at eccentricities e0 = 0; 2.0 cm (0.16h) and 4.0 cm (0.32h).

Keywords: concrete, reinforced concrete, columns, flexibility, composite materials, reinforcement, strength, deformability

The article presents the results of comparison of the average experimental values of the relative deformations of heavy concrete of class B34-35-εb and εbt, which were obtained by testing short compressed columns strengthening with external composite reinforcement based on CFRP. External transverse and longitudinal reinforcement, as well as types of stress-strain state were varied: conditionally centrally compressed elements (e0 = 0); elements loaded at small eccentricities, ie at e0 = 2.0 cm (0.16h) and large e0 = 4.0 (0.32h). The influence of various variants of composite reinforcement on the change in the stress-strain state of concrete at three values of the axial eccentricity e0 is estimated.

Keywords: concrete, reinforced concrete, reinforcement, prototypes, composite, compression, stretching, relative deformations

Presented the general selection of external composite strengthening, based on the use of the above characteristics of the materials for the strengthened elements of the rectangular profile.

Keywords: concrete, reinforced concrete, composite strenghtening, steel, calculation method, strength, capacity

Have been given the substantiation of the need for preliminary testing of concrete beams on the transverse force. Their goal is to determine the effect of inclined cracks formed at the operating load levels, on the efficiency of the composite reinforcement in the near support sections.   The results of these tests, obtained with the shear span 1,5h0; 2h0 and 2,5 h0, that significantly affects the nature of inclined cracks. According to the results of an experiment formulated recommendations for the design of composite reinforcement.

Keywords: concrete, reinfrcement, reinforced concrete composite, CFRP, strengthening, crack, stress level, clamp, shear span, strength

Presented and analyzed the data of the test results of concrete columns with the flexibility of λh=10 and λh=20, the strengthening of the external carbon fiber reinforcement. Borders impact of the various options strengthen influence on strength and deformability of columns and efficiency of composite materials installed.

Keywords: concrete, reinforcement, reinforced concrete composite, eccentricity, flexibility, capacity, strength, deformability, strengthening

in addition to standards are the basic concepts and methodology of selection of the outer cross-sectional area of the composite strengthening for bent and eccentrically-compressed elements. Calculation formulas are based on the classical equations of statics.

Keywords: concrete, reinforced concrete, reinforcement, steel, composite, carbon, strength, load bearing capacity

The data on the bearing capacity of short reinforced concrete columns with the flexibility λh = 10 strengthened by CFRP, the action of axial load, eccentricity e0 = 4cm. Effectiveness of various options for strengthening was determined, provided the action force outside core-section.

Keywords: concrete, reinforced concrete, steel, rebar, composite, carbon fiber, strength, load-bearing capacity.

Presented and analyzed data on the results of tests of short reinforced concrete columns with the flexibility λh = 10 strengthened by CFRP for external applying force with an eccentricity e0 = 2 cm. The effect of strengthening on the bearing capacity and deformability of columns when a load is applied to the inside of the core-section.

Keywords: concrete, reinforced concrete, reinforcement, CFRP, load, strength, deformability.

The article discusses issues related to the study of the influence on the deformability of concrete beams of heavy concrete reinforcing steel to replace the carbon fiber arranged in two rows. Found that delamination of the composite beams with reinforcement throughout the range of loads up to 46-54% compared with the reference.

Keywords: concrete, steel, carbon-fiber reinforcement, test samples, strength, steps of loading, deformability, cracking, load level

The article discusses issues related to the strength of the normal sections of reinforced concrete beams in which the steel reinforcement is completely or partially replaced by a carbon fiber rod arranged in two rows. Found that the strength of these beams is only 13% higher than that of the reference.

Keywords: concrete, steel, composite reinforcing, test samples, strength, failure modes, load level

The article presents a brief overview of the results of a study of the compressed elements in our country and abroad, reinforced composite materials. Noted that in Russia this question is poorly understood. Represented a broad research program developed by the Department JBK RSSU aimed to fill these questions.

Keywords: concrete, steel, carbon-fiber reinforcement, test samples, strength, deformability, cracking.