Axial tests demonstrate that strengthening reinforced concrete columns with carbon fiber reinforced plastic (CFRP) significantly improves their performance through lateral restraint. The circular winding creates a triaxial compression effect, increasing concrete strength and load-bearing capacity. The slows of carbon fiber brittle fracture, increases ductility, suppresses microcracks, and improves seismic resistance. This technology is lightweight, corrosion-resistant, and has low operating costs.
The effectiveness of the reinforcement depends on the number of layers and the winding pitch. Cylindrical columns respond better to reinforcement; square columns require rounded corners (radius ≥20 mm) to prevent stress concentration. Two to three layers of CFRP are recommended. This method is particularly effective for columns with insufficient load-bearing capacity, low ductility, or in seismic conditions.

Keywords: carbon fiber, reinforcement for reinforced concrete columns, compressive load bearing capacity

This article presents a new method of strengthening reinforced concrete columns using metal and composite materials. The analysis of existing traditional and modern methods of strengthening of reinforced concrete compressed elements has been carried out and their main disadvantages have been identified, taking into account which a new reinforcement method has been developed. This study presents the results of testing the effectiveness of a new reinforcement method, describes in detail the basic schemes, technology and procedure for performing reinforcement work. The results of the conducted experimental studies are presented. The strength of the control samples was compared with the reinforced ones. Proposals have been developed to strengthen reinforced concrete columns with metal elements arranged longitudinally and composite materials glued in the form of clamps with fibers arranged in the transverse direction.

Keywords: steel, reinforced concrete, heavy concrete, test, rack, composite material

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.