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 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

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 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.

This paper addresses the testing results of steel rods with grade A500 and A600, which used as a conventional reinforcement. It was investigated the strength properties of carbon and fiberglass sheets with different number of material layers. The results are compared with the data given in the quality certificates.

Keywords: fiberglass, carbon frp sheets, laminates, sheets of carbon and fiberglass, the ultimate load ,strength