Solovyeva A.I.

Assistant of the Department of Reinforced Concrete and Stone Structures, Junior Researcher at the Department of Scientific Research of the Don State Technical University, Don State Technical University

Experimental analysis of a new high-tech method of strengthening reinforced concrete structures based on the use of metal and CFRP materials

https://doi.org/10.58224/2618-7183-2025-8-6-9
Аннотация
This paper presents a large-scale experimental analysis of a new high-tech method for strengthening reinforced concrete columns using metal and CFRP materials. The research is justified by evaluating existing traditional and modern methods of strengthening reinforced concrete compressed elements, identifying their main drawbacks, and taking these into account, a new strengthening method was developed. To study the large-scale effect of the new high-tech metal and composite-based strengthening method, two groups of a total of 46 reinforced concrete column samples with different flexibilities were designed and tested for central and eccentric compression until failure. The main test parameters included column flexibility, load application eccentricity, internal and external metal reinforcement, spacing, and cross-sectional area of composite strengthening. The study investigated the influence of the above-mentioned variable factors on the failure pattern, ultimate strength, peak stress, and deformation characteristics of columns strengthened with carbon fiber composite materials (CFRP). The results showed that reinforced concrete columns strengthened with CFRP, having the same dimensions and tested under the same load application eccentricities, demonstrated different increases in ultimate strength compared to unstrengthened columns. Peak stress increased with an increase in the cross-sectional area of metal reinforcement and decreased with an increase in the distance between composite stirrups. Ultimate axial strains of strengthened samples increased with a decrease in the distance between composite stirrups. The difference in the cross-sectional area of composite strengthening did not have a significant impact on the load-bearing capacity and ultimate strains of reinforced concrete strengthened structures.
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The high-tech and effective method of strengthening reinforced concrete structures with CFRP materials with preliminary modification of the cross-section shape

https://doi.org/10.58224/2618-7183-2024-7-6-7
Аннотация
It is known that the effectiveness of reinforcement with CFRP composite materials of reinforced concrete structures of round or oval sections is significantly higher than rectangular or square ones due to the uneven distribution of internal limiting pressure in the latter. This study is devoted to the study of the effectiveness of a new method of strengthenet based on a preliminary change in the shape of reinforced concrete and concrete columns of square section. The sharp corners of the columns create a concentrating internal limiting stress in the CFRP composite cage, while the amplification system collapses prematurely, and the amplification efficiency is greatly reduced. To comprehensively solve this problem, the authors have manufactured, strengthened and tested a number of reinforced concrete columns with different variants of CFRP composite reinforcement. For the purity of the experiment, reference racks were also made, not reinforced, and reinforced with CFRP composite clips without rounding. All prototypes were made of the same materials, as well as strengthened and tested using the same techniques. The paper describes the features of traditional and modern methods of composite strengthenet of reinforced concrete columns, analyzes the main disadvantages of existing strengthenet methods and, based on this, presents a new strengthenet method that allows more efficient use of composite materials in the transverse direction. The new strengthenet method is described in detail, the main schemes and procedure for performing strengthenet work are presented. The final stage of the work is the main results of an experimental study, where the characteristics of reference samples were compared with similar structures strengthened in the transverse direction with CFRP composite materials. The experimental results show that the proposed amplification method is highly effective. For the best effect, it is proposed that the material used for rounding has higher strength and less deformability compared to concrete columns.
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