Proposals for Determining the Relative Deformations Design Value of ε_b3 Concrete in Volumetric Deformation Conditions

Abstract:

The article presents the studies’ results on the deformability and strength of reinforced concrete racks reinforced with composite materials with the characteristics stretching beyond the limits established by the norms of Russia, namely: the λ_h structures flexibility exceeding the value 15, the ratio of the cross-section sides equal to 1.5 and the eccentricity of the load application e₀ exceeding 0.1h. The results of the tested racks calculations are analyzed according to BC 164.1325800.2014, which in some cases confirmed the inexpediency of using composite materials. However, according to the results of our experiment, an increase in the strength of a number of racks with the characteristics that go beyond the recommended standards was found. The purpose of this study is to check the methodology for calculating Russian norms for the compressed reinforced concrete elements, the parameters of which are outside the limits recommended by the norms, to develop proposals for improving the calculation based on the obtained experimental data and to determine the concrete deformability effect on the change in bearing capacity. The article discusses flexible struts, reinforced with composite materials, located in the transverse direction. The experimental data results on the deformability of concrete and the strength of struts reinforced in the transverse direction are presented. The calculation methodology, compiled in accordance with Russian standards, the calculation results of which are the theoretical values ​​of the deformability of concrete and the strength of the racks, is considered. After comparison, a significant underestimation of the theoretical strengths and a mismatch in the struts’ concrete deformations were revealed. It was found that the change in compressive deformations of concrete depends on the external composite reinforcement. Theoretical values , calculated according to the current standards, have significant discrepancies with the experimental ones. Based on the experiments’ results analysis, in the methodology of norms for calculating the ultimate compressive deformations of concrete the suggestions that take into account the type and percentage of composite reinforcement and ensure a good agreement between experimental and theoretical values have been made. After the introduction of the coefficient into normative calculation, new data on the theoretical strength of the struts were obtained, which showed significantly better convergence with the experimental data.

• Periodical: Materials Science Forum (Volume 1043)
• Pages: 155-162
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1043.155
• Online since: August 2021
• Authors: Sergey Georgiev*, Dmitriy Mailyan, Alik Blyagoz
• Keywords: Carbon Fiber Reinforced Plastic, Composite Material, Compressed Elements, Concrete, Deformations, External Reinforcement, Reinforced Concrete

References

[1] M. Arduini, and A. Nanni, Behavior of Precracked RC Beams Strengthened with Carbon FRP Sheets, Journal of Composites for Construction. U.S.A. 1(2) (1997) 63-70.

DOI: 10.1061/(asce)1090-0268(1997)1:2(63)

[2] E. David, C. Djelal, and F. Buyle-Bodin, Repair and strengthening of reinforced concrete beams using composite, 7th Int. conf. on Struct. Faults and Repair. 2 (1997) 169-173.

[3] Externally bonded FRP reinforcement for RC structures. Bulletin No.14, FIB-TG9.3., 2001. Technical Rep., Lausanne, Switzerland.

DOI: 10.35789/fib.bull.0014.ch01

[4] А.N. Kostenko, Strength and deformability of centrally and eccentrically compressed brick and reinforced concrete columns reinforced with coal and fiberglass, Abstract. diss. Cand. tech. Sciences, Moscow, (2010).

[5] P.P. Polskoy, D.R. Mailyan, D.A. Dedukh, S.V. Georgiev, Design of reinforced concrete beams in a case of a change of cross section of composite strengthening reinforcement, Global Journal of Pure and Applied Mathematics. 12(2) (2016) 1767-1786.

[6] A. Shilov, P. Polskoy, D. Mailyan, P. Shilov, Initial crack effect on the strength of oblique cross sections of reinforced concrete beams strengthened with carbon fiber, Web of Conferences. 2018 International Science Conference on Business Technologies for Sustainable Urban Development, SPbWOSCE 2018. (2019) 01053.

DOI: 10.1051/e3sconf/201911001053

[7] P. Polskoy, D. Mailyan, S. Georgiev, V. Muradyan, The strength of compressed structures with cfrp materials reinforcement when exceeding the cross-section size, E3S Web of Conferences. (2018) 02060.

DOI: 10.1051/e3sconf/20183302060

[8] P.P. Polskoy, D.R Mailyan, S.V. Georgiyev, Strength and deformability of flexible reinforced struts at large eccentricities, Scientific Review. 12(2) (2014) 496-499.

[9] P.P. Polskoy, S.V. Georgiyev, Characteristics of the materials used in the study of short and flexible legs, reinforced with CFRP, Scientific Review. 10(2) (2014) 411-414.

[10] P.P. Polskoy, А. Mihub, S.V. Georgiyev, Methods of reinforcement with composite materials and testing of reinforced concrete elements, Engineering Herald of the Don. 2 (2013). Information on ivdon.ru/magazine/archive/n2y2013/1687.

[11] D.R. Mailyan, P.P. Polskoy, S.V. Georgiyev, The design of frames and test schemes for experimental stands, reinforced with CFRP, Scientific Review. 10(3) (2014) 667-670.

[12] P.P. Polskoy, S.V. Georgiyev, About the research program of compressed reinforced concrete elements reinforced with composite materials based on carbon fiber, Scientific Review. 10(3) (2014) 662-666.

[13] А.V. Fedorov, V.N. Aksenov, On the question of the use of high-strength concrete in compressed elements of high-rise buildings, Engineering Herald of the Don. 3(50) (2018) 102.

[14] V.N. Aksenov, N.B. Aksenov, Study of the work of compressed reinforced concrete elements made of high-strength concrete, Construction: new technologies - new equipment. 1 (2017) 27-31.