Behavior of Normal and High Strength Reinforced Concrete Corbels Strengthened with Steel Plates
Received: 18 December 2024 | Revised: 8 January 2025, 21 January 2025, and 31 January 2025 | Accepted: 17 February 2025 | Online: 6 October 2025
Corresponding author: Marwa Abbas Fadel
Abstract
Corbels are short cantilevered structural elements typically extending from walls or columns, characterized by a shear span-to-depth ratio (a/d) less than one. In this study, the structural performance of reinforced concrete corbels strengthened with externally bonded steel plates was evaluated under monotonic vertical loading. The experimental program included six reinforced concrete corbel specimens, each with dimensions of 250 mm span × 150 mm width × 250 mm depth. The investigation focused on three main parameters: concrete compressive strength, that is, 30 MPa for Normal-Strength Concrete (NSC) and 70 MPa for High-Strength Concrete (HSC), the presence or absence of steel plate reinforcement, and two a/d ratios (0.3 and 0.6). The results indicated that the use of steel plates significantly enhanced the structural behavior of the corbels, increasing the ultimate load capacity, crack resistance, and energy absorption. The specimens strengthened with steel plates also demonstrated improved ductility compared to the un-strengthened specimens. These findings confirm that the external steel plate reinforcement is an effective method for enhancing the mechanical performance of both NSC and HSC corbels under vertical loading.
Keywords:
corbels, High Strength Concrete (HSC) , Normal Strength Concrete (NSC), steel plate, monotonic vertical loadingDownloads
References
M. W. Falah, Z. Al-Khafaji, R. Yaseen, D. F. Yousif, K. A. Hamza, and S. S. Radhi, "Finite Element Simulations of the CFRP Retrofitted Hollow Square Columns : Hollow Square Columns," Electronic Journal of Structural Engineering, vol. 22, no. 01, pp. 1–13, May 2022.
M. Falah and Z. Al-khafaji, "Behaviour Of Reactive Powder Concrete Hollow Core Columns Strengthened With Carbon Fiber Reinforced Polymer Under Eccentric Loading," Electronic Journal of Structural Engineering, vol. 22, no. 3, pp. 28–38, Oct. 2022.
Y. A. Ali et al., "Studying the effect of shear stud distribution on the behavior of steel–reactive powder concrete composite beams using ABAQUS software," Journal of the Mechanical Behavior of Materials, vol. 31, no. 1, pp. 416–425, Jan. 2022.
G. Zhang et al., "Reinforced concrete deep beam shear strength capacity modelling using an integrative bio-inspired algorithm with an artificial intelligence model," Engineering with Computers, vol. 38, no. 1, pp. 15–28, Apr. 2022.
A. Y. Pranata, D. Tjitradi, and I. Prasetia, "Horizontal Web Reinforcement Configuration Analysis of Deep Beam Capacity and Behavior using Finite Element Modeling," Engineering, Technology & Applied Science Research, vol. 10, no. 1, pp. 5242–5246, Feb. 2020.
ACI Committee 318, "ACI CODE 318-08: Building Code Requirements for Structural Concrete and Commentary." ACI, USA, 2007.
S. I. Khaleel, B. A. Ali, and Z. S. Othman, "Shear strength and behavior of reinforced concrete corbels containing either carbon fibers or stirrups," ZJPAS, vol. 29, no. 5, pp. 10–21, 2017.
Z. Al‐Khafaji et al., "State-of-Art: Artificial Intelligence Models Era in Modeling Beam Shear Strength," Knowledge-Based Engineering and Sciences, vol. 3, no. 3, pp. 1–63, Dec. 2022.
D. N. Jabbar, A. Al-Rifaie, A. M. Hussein, A. A. Shubbar, M. S. Nasr, and Z. S. Al-Khafaji, "Shear behaviour of reinforced concrete beams with small web openings," Materials Today: Proceedings, vol. 42, pp. 2713–2716, Jan. 2021.
J. M. Yang, J. H. Lee, Y. S. Yoon, W. D. Cook, and D. Mitchell, "Influence of Steel Fibers and Headed Bars on the Serviceability of High-Strength Concrete Corbels," Journal of Structural Engineering, vol. 138, no. 1, pp. 123–129, Jan. 2012.
N. I. FattuhiI and B. P. Hughes, "Reinforced Steel Fiber Concrete Corbels With Various Shear Span-to-Depth Ratios," Materials Journal, vol. 86, no. 6, pp. 590–596, Nov. 1989.
N. I. Fattuhi, "Strength of SFRC Corbels Subjected to Vertical Load," Journal of Structural Engineering, vol. 116, no. 3, pp. 701–718, Mar. 1990.
E. M. Lotfy, H. A. Mohamadien, and H. M. Hassan, "Effect of web reinforcement on shear strength of shallow wide beams," International Journal of Engineering and Technical Research (IJETR), vol. 2, no. 11, pp. 98–107, Nov. 2014.
P. Ciobanu, N. Taranu, S. Popoaei, and D. Banu, "Structural Response of Reinforced Concrete Beams Strengthened in Flexure with Near Surface Mounted Fibre Reinforced Polymer Reinforcement Experimental Setup," Journal of Polytechnic Institute of Lasi, vol. 58, no. 4, pp. 9–16, Sep. 2012.
I. Ivanova, J. Assih, A. Li, and D. Dontchev, "Study of Strengthened Reinforced Concrete Short Corbel by Externally Bonded Carbon Fibres Fabrics," in 14th International Multidisciplinary Scientific GeoConference SGEM 2014, 2014, pp. 315–322.
S. M. Kim, Y. K. Cho, and B. K. Park, "Experimental and Numerical Evaluation of Reinforced Concrete Bracket Design for Supporting Middle Slab in Double-Deck Tunnel," KSCE Journal of Civil Engineering, vol. 23, no. 8, pp. 3682–3693, Aug. 2019.
E. S. Khalifa, "Macro-mechanical strut and tie model for analysis of fibrous high-strength concrete corbels," Ain Shams Engineering Journal, vol. 3, no. 4, pp. 359–365, Dec. 2012.
H. M. Thiyab, "Behavior of Reinforced Concrete Brackets Strengthened with Different Techniques," International Journal of Civil Engineering and Technology (IJCIET), vol. 8, no. 4, pp. 868–883, Apr. 2017.
Q. M. Shakir and S. D. A. Alsaheb, "High strength self-compacting corbels retrofitted by near surface mounted steel bars," Pollack Periodica, vol. 18, no. 1, pp. 106–112, Oct. 2022.
Iraqi Specifications, "IQS 5/2005 for Portland Cement." Ministry of Planning, Central Organization for Standardization and Quality Control, Baghdad, Iraq, 2005.
Iraqi Specifications, "IQS 45/1984 for for Aggregates of Natural Resources used for Concrete and Construction." Ministry of Planning, Central Organization for Standardization and Quality Control, Baghdad, Iraq, 1984.
C21.03, "ASTM C370-12: Standard Test Method for Moisture Expansion of Fired Whiteware Products." ASTM INTERNATIONAL, Nov. 04, 2016.
C09.23, "ASTM C494:Standard Specification for Chemical Admixtures for Concrete." ASTM INTERNATIONAL, Aug. 06, 2024.
C09.24, "ASTM C1240-15: Standard Specification for Silica Fume Used in Cementitious Mixtures." ASTM INTERNATIONAL, Mar. 05, 2020.
W. B. Siao, "Shear Strength of Short Reinforced Concrete Walls, Corbels, and Deep Beams," Structural Journal, vol. 91, no. 2, pp. 123–132, Mar. 1994.
H. K. al-Qaraghuli and N. N. Abd al-Hamid, "Effect of Using Slurry Infiltrated Fiber Concrete on the Behavior of Reinforced Concrete Corbels," al-Mustansyriah University College of Engineering, vol. 25, no. 31, pp. 69–77, Dec. 2021.
R. M. F. Canha, D. A. Kuchma, M. K. El Debs, and R. A. de Souza, "Numerical analysis of reinforced high strength concrete corbels," Engineering Structures, vol. 74, pp. 130–144, Sep. 2014.
J. M. Aliewi, "Behavior and Strength of Self-Compacting Fiber Reinforced Concrete Corbels," Ph.D. Thesis, Al-Mustansiriya Univiversity, Baghdad, Iraq, 2014.
Y. K. Yong and P. Balaguru, "Behavior of Reinforced High‐Strength‐Concrete Corbels," Journal of Structural Engineering, vol. 120, no. 4, pp. 1182–1201, Apr. 1994.
V. G. Belardi, P. Fanelli, and F. Vivio, "Bending analysis with Galerkin method of rectilinear orthotropic composite circular plates subject to transversal load," Composites Part B: Engineering, vol. 140, pp. 250–259, May 2018.
H. Kabir and M. M. Aghdam, "A robust Bézier based solution for nonlinear vibration and post-buckling of random checkerboard graphene nano-platelets reinforced composite beams," Composite Structures, vol. 212, pp. 184–198, Mar. 2019.
Downloads
How to Cite
License
Copyright (c) 2025 Marwa Abbas Fadel, Waleed Awad Waryosh

This work is licensed under a Creative Commons Attribution 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain the copyright and grant the journal the right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) after its publication in ETASR with an acknowledgement of its initial publication in this journal.