Numerical Methods in Civil Engineering

Numerical Methods in Civil Engineering

Numerical Investigation of the Effect of CFRP Sheet Angle and Arrangement on the Shear Capacity of Reinforced Concrete Deep Beams

Document Type : Research

Authors
Alireza Abbaszadeh 1
Taleb Hasheminezhad 2
1 Assistant Professor, Department of Civil Engineering, Ilam University, Ilam, Iran
2 Graduated civil Engineering, Razi University, Kermanshah, Iran
10.61882/NMCE.2602.1131
Abstract
Deep beams generally suffer from limited shear capacity and ductility due to their specific aspect ratio and the significant contribution of shear deformation to their overall response. Consequently, various methods have been employed to strengthen these structural members. Among these, reinforcing the beam web with Carbon Fiber Reinforced Polymer (CFRP) sheets is considered one of the most effective solutions. Given the inherent limitations of conventional steel reinforcement in significantly enhancing shear capacity and ultimate strength, CFRP sheets have emerged as an effective alternative and are currently the focus of extensive research.
In this study, the shear behavior of CFRP-strengthened deep beams is investigated using numerical simulation in the ABAQUS finite element software. To this end, sixteen deep beam specimens with constant longitudinal reinforcement but varying shear span-to-depth ratios (a/d) were designed and analyzed under two concentrated loads equidistant from the supports. From this set, four models served as control specimens (un-strengthened), and the remaining twelve models were strengthened in the shear zone using CFRP sheets. The results indicated that the maximum shear contribution of CFRP is achieved with a 135 degree orientation, particularly in beams exhibiting shear-dominant behavior (low a/d ratio). Specifically, an increase in ultimate capacity up to 50% was observed, along with a reduction in rebar stress compared to the strengthened state.
Keywords
Reinforced Concrete Deep Beam
CFRP
Shear Strengthening
Finite Element Method
Subjects
[1] “A Simple Approach to Predict the Shear Capacity and Failure Mode of Fix-ended Reinforced Concrete Deep Beams based on Experimental Study,” Int. J. Eng., vol. 32, no. 4, Apr. 2019, doi: 10.5829/ije.2019.32.04a.03.
[2] A. Al-khreisat, M. Abdel-Jaber, and A. Ashteyat, “Shear Strengthening and Repairing of Reinforced Concrete Deep Beams Damaged by Heat Using NSM–CFRP Ropes,” Fibers, vol. 11, no. 4, p. 35, Apr. 2023, doi: 10.3390/fib11040035.
[3] A. Abadel, “Shear strengthening of deficient RC deep beams using NSM FRP system: Experimental and numerical investigation”.
[4] A. Kumar and R. Jangid, “Experimental and analytical study of shear strengthening of deep RC beams using externally bonded CFRP system,” Innov. Infrastruct. Solut., vol. 9, no. 7, p. 284, 2024.
[5] A. Arabzadeh and H. Karimizadeh, “Experimental study of RC deep beams with opening and FRP composites installed by means of EBR and EBROG methods,” Constr. Build. Mater., vol. 208, pp. 780–791, May 2019, doi: 10.1016/j.conbuildmat.2019.03.055.
[6] A. Kumari, S. S. Patel, and A. N. Nayak, “Shear Strengthening of RC Deep Beam Using Externally Bonded GFRP Fabrics,” J. Inst. Eng. India Ser. A, vol. 99, no. 2, pp. 341–350, Jun. 2018, doi: 10.1007/s40030-018-0272-0.
[7] H. C. Akkaya, C. Aydemir, and G. Arslan, “An experimental research on reinforced concrete deep beams fully wrapped with fiber reinforced polymers against shear,” Case Stud. Constr. Mater., vol. 17, p. e01198, Dec. 2022, doi: 10.1016/j.cscm.2022.e01198.
[8] N. Al-Bayati, B. Muhammad, and S. Sadkhan, “Retrofitting of shear strength self-compacting reinforced concrete deep beams with FRP,” MATEC Web Conf., vol. 162, p. 04016, 2018, doi: 10.1051/matecconf/201816204016.
[9] S. Ma, J. Sun, and T. Xu, “Numerical Analysis of Shear Contribution of CFRP-Strengthened RC Beams by Different Bond-Slip Models,” Int. J. Concr. Struct. Mater., vol. 19, no. 1, p. 4, Jan. 2025, doi: 10.1186/s40069-024-00728-2.
[10] S. Ma, J. Sun, and T. Xu, “Numerical Analysis of Shear Contribution of CFRP-Strengthened RC Beams by Different Bond-Slip Models,” Int. J. Concr. Struct. Mater., vol. 19, no. 1, p. 4, Jan. 2025, doi: 10.1186/s40069-024-00728-2.
[11] Y.-L. Bai, J.-G. Dai, and J. G. Teng, “Buckling of steel reinforcing bars in FRP-confined RC columns: An experimental study,” Constr. Build. Mater., vol. 140, pp. 403–415, Jun. 2017, doi: 10.1016/j.conbuildmat.2017.02.149.
[12] H. K. Lee, S. H. Cheong, S. K. Ha, and C. G. Lee, “Behavior and performance of RC T-section deep beams externally strengthened in shear with CFRP sheets,” Compos. Struct., vol. 93, no. 2, pp. 911–922, Jan. 2011, doi: 10.1016/j.compstruct.2010.07.002.
[13] J. A. Bhat, “Effect of CFRP-Reinforcement variation on the strength parameters of different timber beams,” Mater. Today Proc., vol. 44, pp. 2785–2791, 2021, doi: 10.1016/j.matpr.2020.12.783.
[14] K. S. Ismail, M. Guadagnini, and K. Pilakoutas, “Strut-and-Tie Modeling of Reinforced Concrete Deep Beams,” J. Struct. Eng., vol. 144, no. 2, p. 04017216, Feb. 2018, doi: 10.1061/(ASCE)ST.1943-541X.0001974.
[15] P. D. Zararis, “Shear Compression Failure in Reinforced Concrete Deep Beams,” J. Struct. Eng., vol. 129, no. 4, pp. 544–553, Apr. 2003, doi: 10.1061/(ASCE)0733-9445(2003)129:4(544).
[16] M. A. Javed, M. Irfan, S. Khalid, Y. Chen, and S. Ahmed, “An experimental study on the shear strengthening of reinforced concrete deep beams with carbon fiber reinforced polymers,” KSCE J. Civ. Eng., vol. 20, no. 7, pp. 2802–2810, Nov. 2016, doi: 10.1007/s12205-016-0739-3.
[17] M. I. Kabir, M. Subhani, R. Shrestha, and B. Samali, “Experimental and theoretical analysis of severely damaged concrete beams strengthened with CFRP,” Constr. Build. Mater., vol. 178, pp. 161–174, Jul. 2018, doi: 10.1016/j.conbuildmat.2018.05.038.
[18] M. F. Jassim, Y. J. Lafta, and H. S. Malik, “Shear Behavior of Reinforced Concrete Beams with Different Arrangements of Externally Bonded Carbon Fiber-Reinforced Polymer,” J. Eng., vol. 2023, pp. 1–9, Jul. 2023, doi: 10.1155/2023/1465410.
[19] A. Szewczak, “Influence of Epoxy Glue Modification on the Adhesion of CFRP Tapes to Concrete Surface,” Materials, vol. 14, no. 21, p. 6339, Oct. 2021, doi: 10.3390/ma14216339.
[20] K. Śliwa-Wieczorek, K. A. Ostrowski, J. Jaskowska-Lemańska, and A. Karolak, “The Influence of CFRP Sheets on the Load-Bearing Capacity of the Glued Laminated Timber Beams under Bending Test,” Materials, vol. 14, no. 14, p. 4019, Jul. 2021, doi: 10.3390/ma14144019.
[21] M.-S. Jo, H.-G. Kim, D.-H. Kim, S.-A. Lim, H. Kong, and K.-H. Kim, “Evaluation of Behavior Characteristics of Reinforced Concrete Beam Shear Strengthening with Different FRCMs,” Buildings, vol. 14, no. 12, p. 3949, Dec. 2024, doi: 10.3390/buildings14123949.
[22] F. Zhang and L. Gao, “Finite Element Model for Analysis of the Spatial Interfacial Debonding of FRP from Concrete,” Adv. Compos. Lett., vol. 26, no. 3, pp. 89–100, doi: https://doi.org/10.1177/096369351702600305.
[23] S. S. Chiriki and G. S. Harsha, “Finite element analysis of RC deep beams strengthened with I-section and truss reinforcement,” Mater. Today Proc., vol. 33, pp. 156–161, 2020, doi: 10.1016/j.matpr.2020.03.579.
[24] M. Ghalla, G. Elsamak, A. El-Zohairy, O. Youssf, S. Khairy, and A. Badr el-din, “Experimental investigation on the structural performance of strengthened reinforced concrete deep beams using steel-based and SHCC techniques,” in Structures, Elsevier, 2026, p. 111074.
[25] G. Priyasri, S. Gollapalli, P. J. Varma, S. K. Muniasamy, P. Praveena, and S. Annam, “Fusion-Based Data-Driven Strength Prediction of Bamboo Fiber-Reinforced Concrete for Sustainable Construction,” 2026.
[26] M. Samhan, M. Shhabat, M. Abdel-Jaber, and A. Ashteyat, “Shear strengthening and rehabilitation of heat-damaged RC deep beams with openings using CFRP: experimental and numerical study,” J. Asian Archit. Build. Eng., pp. 1–23, 2026.
[27] “Defining parameters for concrete damage plasticity model,” Chall. J. Struct. Mech., 2015, doi: 10.20528/cjsmec.2015.07.023.
[28] M. Shabanlou, M. Mofid, and A. Tavakoli, “Experimental and Numerical Study on the Behavior of Reinforced Concrete Deep Beams with Normal-Strength and High-Strength Concrete After Being Exposed to Fire,” Arab. J. Sci. Eng., vol. 49, no. 10, pp. 13457–13476, Oct. 2024, doi: 10.1007/s13369-023-08676-x.
Numerical Methods in Civil Engineering
Volume 10, Issue 4
Spring 2026
Pages 12-29

  • Receive Date 25 February 2026
  • Accept Date 03 August 2026