| Ductility is an important mechanical property of concrete structures, in tensile members, as it is the property that allows the structural member to deform plastically long before the failure point. To increase the deformation period of the beams, i.e., the ductility of failure. In the current paper, four reinforced concrete beams were modeled and compared using nonlinear finite element analysis. Reinforced concrete beams are developed and analyzed by using ABAQUS commercial software. Nonlinear material behavior, as it relates to steel reinforcing bars and plain concrete, is simulated. The effect of the change of the concrete compressive strength in the upper one-third of the beams on the ductility, the ultimate strengths, and the mode of failure of beams are investigated. One of the beam specimens was used as a reference. The change in the compressive strengths in the compressive zone was in the range of 27, 31, 37, and 42 MPa. The results of the analysis of the modeled beams were validated and compared with beams tested experimentally by previous researchers. It was found that load-deflection curves of the FE modeling of the beams match the same findings in the experiments. Furthermore, to investigate different techniques in strengthening the upper third of the beams for enhancing ultimate strength and ductility behavior, a parametric study was performed by modeling beam specimens consisting of two groups, among them using a hybrid of Carbon nanotubes (CNTs) & steel fiber, which was added to the concrete mixture of the upper third of a beam specimen and was used as strengthening layer stuck to the top layer of the compression zone of another beam. It was found that the beam that was strengthened in the compression zone by the layer of the concrete containing the mixture of the CNTs & steel fibers increased the beams' strength and ductility; hence, the ultimate load and deflection were increased by 63%, and 40%, respectively. |
- A. H. Tarek, H. M. Elsanadedy, Y. A. Al-Salloum, S. H. Alsayed, Experimental and numerical investigation for the flexural strengthening of RC beams using near-surface mounted steel or GFRP bars, Constr. Build. Mater., (2013) 145-161.
- I. A. Saeed, S. Al-Mahaidi, T. S. Al-Attar, B. S. Al-Shathr, Flexural Behavior of RC Beams Strengthened by NSM-CFRP Laminates or Bars, Eng. Technol. J., 36 (2018) 358-367. https://doi.org/10.30684/etj.36.4A.1
- M. Huusain, M. Kuniedo and N. Nakamuro, Strength and ductility of RC beams strengthened with steel reinforced strain hardening cementitious composites, Cem. Concr. Compos., 34 (2012).
- Z. J. Yasen, A. M. Lateef and A. S. Khazaal, Structural behavior of simply supported two layers reinforced concrete (normal strength mortar and 3-dimension glass fiber), beams, Tikrit J. Eng. Sci., 28 (2021) 93- 106. https://doi.org/10.25130/tjes.28.2.08
- D. Assi,Verification and Parametric Analysis of Shear Behavior of Reinforced Concrete Beams using Non-linear Finite Element Analysis, J. Eng., 29 (2023) 184-202. https://doi.org/10.31026/j.eng.2023.11.11
- H. T. Hu, F. M.Lin, Y. Y.Jan, Non-linear finite element analysis of reinforced concrete beams strengthened by strengthened by fiber- reinforced plastics, Compos. Struct., 63 (2004) 271-281. https://doi.org/10.1016/S0263-8223(03)00174-0
- V. Desmaris, M. A. Saleem, S. Shafiee, Examining Carbon Nanofibers: Properties, growth, and applications, J. Mag. IEEE Nanatechnol. Mag., 9 (2015) 33-38. https://doi.org/10.1109/MNANO.2015.2409394
- X. L. Xie, Y. W. Mai, X. P. Zhou, Dispersion and alignment of carbon nanotubes in polymer matrix: a review, Mater. Sci. Eng. R Rep., 49 (2005) 89-112. https://doi.org/10.1016/j.mser.2005.04.002
- S. S. Hasan, A. Khitab, S. Ahmed, R. Arsalan, Improving mechanical performance of cement composites by addition of CNTs addition, Procedia Struct. Integrity, Elesevier Italian Group of Fracture Conference, 3 (2017) 11-17. https://doi.org/10.1016/j.prostr.2017.04.003
- L. Silvestro, P. J. Gleize, Effect of carbon nanotubes on compressive, flexural and tensile strengths of Portland cement-based materials: A systematic literature review, Constr. Build. Mater., 264 (2020) 120237. https://doi.org/10.1016/j.conbuildmat.2020.120237
- P. Zhu, Q. Jia, Z. Li, Y. Wu, Z. J. Ma, Theoretical Model for the Stress–Strain Curve of CNT-Reinforced Concrete under Uniaxial Compression, Buildings, 14 (2024) 418. https://doi.org/10.3390/buildings14020418
- S. A. Hassan, A. E. Ajeel, Effect of Concrete Compressive Strength and Compression Reinforcement in Compression Zone on the Ductility of Reinforced Concrete Beams, Eng. Technol. J., 32 (2016) 1106-1116. http://dx.doi.org/10.30684/etj.32.5A.2
- ABAQUS. Analysis of the user's manual version 2014.
- A. Belarbi, T. Hsu, Constitutive laws of concrete in tension and reinforcing bars stiffened by concrete, ACI Struct. J., 91 (1994) 465-474. https://doi.org/10.14359/4154
- C. Maheswaran, S. Prakash, A. Rajagopal, Analytical and finite element studies on hybrid FRP strengthened RC column elements under axial and eccentric compression, Comput. Struct., 184 (2017) 234-248. http://dx.doi.org/10.1016/j.compstruct.2017.09.109
- Y. Mohammadi, S. P. Singh, S. K. Kaushik, Properties of Steel Fibrous Concrete Containing Mixed Fibres in Fresh and Hardened State, Constr. Build. Mater., 22 (2008) 956-965. https://doi.org/10.1016/j.conbuildmat.2006.12.004
- Z. L. Wang, Y. S. Liu, R. F. Shen, Stress-Strain Relationship of Steel Fibre-Reinforced Concrete Under Dynamic Compression, Constr. Build. Mater., ASCE, 22 (2008) 811-819. https://doi.org/10.1016/j.conbuildmat.2007.01.005
- G. Giaccio, J. M. Tobes, R. Zerbino, Use of Small Beams To Obtain Design Parameters of Fibre Reinforced Concrete, Cem. Concr. Compos., 30 (2008) 297-306. https://doi.org/10.1016/j.cemconcomp.2007.10.004
- Z. Deng, J. Li, Mechanical Behavior of Concrete Combined with Steel and Synthetic Macro-Fibres, Int. J. Phys. Sci., 1 (2006) 57-66.
- D. A. Fanella, A. E. Naaman, Stress-Strain Properties of Fiber Reinforced Mortar in Compression, ACI, J., 82 (1985) 475-483. https://doi.org/10.14359/10359
- R. N. Swamy, The Technology of Steel Fibre Reinforced Concrete for Practical Applications, ICE Proceedings, 56 (1974) 143-159. https://doi.org/10.1680/iicep.1974.4084
- Y. Chi, M. Yu, L. Huang, L. Xu, Finite element modeling of steel-polypropylene hybrid fiber reinforced concrete using modified concrete damaged plasticity, Eng. Struct., 148 (2017) 23-35. https://doi.org/10.1016/j.engstruct.2017.06.039
- Tomaszewicz, A. Betongens Arbeidsdiagram; SINTEF REP. NO. STF 65A84605; (1984) the foundation for industrial and technical research: Trondheim, Norway.
- D. A. Hordijk, Tensile and tensile fatigue behavior of concrete; experiments, modelling and analyses, Heron, 37 (1992) 3-79.
- ACI Committee 318, Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary, American Concrete Institute, Farmington Hills, MI, 2019, pp 623.
- Chen, Z. Y., Zhu, J. Q. and Wu, P. G. (1992), High strength concrete and its application, Beijing: Tsinghua University Press, China.
- P. Desayi and S. Krishnan, Equation for the stress–strain curve of concrete, J. Proce., 61 (1964) 345-350. https://doi.org/10.14359/7785
- M. Chellapandian, S. S.Prakash, A.Rajagopal, Analytical and finite element studies on hybrid FRP strengthened RC column elements under axial and eccentric compression, Compos. Struct., 184 (2017) 234-248. https://doi.org/10.1016/j.compstruct.2017.09.109
|
