Investigation of Astral CFRP Strengthening Effect on the Punching Shear Response of Self-Compacting RC Two-Way Slabs with Openings
Article Sidebar
Main Article Content
Abstract
Fiber Reinforced Polymers (FRP) are widely employed for the strengthening and rehabilitation of reinforced concrete (RC) structures. Openings are frequently incorporated into structural members, such as slabs, to accommodate essential building services (e.g., pipes, electrical conduits). However, these openings inevitably comproise structural integrity, often leading to a significant reduction in performance metrics such as punching shear capacity. This degradation can be mitigated through the application of Carbon Fiber Reinforced Polymer (CFRP) sheets. This experimental study investigates the punching shear behavior of self-compacting concrete (SCC) two-way slabs with inherent square openings, strengthened with CFRP sheets configured in a square pattern around the openings. The experimental program comprised five 1000 mm x 1000 mm x 75 mm slabs, identically reinforced, including one solid control specimen and one unstrengthened slab with an opening as reference specimens. The remaining three slabs, each featuring an opening, were strengthened with one, two, and three layers of CFRP, respectively. The results indicate that while the CFRP strengthening technique did not fully restore the ultimate load capacity to that of the solid slab, it significantly enhanced the performance compared to the unstrengthened slab with an opening. Improvements were observed in the first-crack load, ultimate load, and stiffness. Specifically, the first-crack load for the strengthened specimens (AW1, AW2, AW3) exceeded that of the unstrengthened specimen by 25.3%, 41.8%, and 40.5%, respectively. Correspondingly, the ultimate load capacity was enhanced by 19.2%, 21.0%, and 22.9%.
Article Details
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Licensed under a CC-BY license: https://creativecommons.org/licenses/by-nc-sa/4.0/
How to Cite
References
References
Z. M. Saad and A. S. Al Amli, “Shear punching behavior for flat slabs with CFRP and openings,” Eng. Technol. Appl. Sci. Res., vol. 15, no. 2, pp. 22239–22245, 2025. doi: 10.48084/etasr.9880.
N. M. J. Al-Quraishy, T. M. S. Alrudaini, and Y. J. Lafta, “Effect of openings on the performance of continuous RC one-way slabs,” Eng. Technol. Appl. Sci. Res., vol. 15, no. 2, pp. 20959–20965, 2025. doi: 10.48084/etasr.9743.
H. R. Ali and A. S. Al Amli, “CFRP strengthening of circular geo-polymer concrete slab with and without openings,” Eng. Technol. Appl. Sci. Res., vol. 15, no. 2, pp. 21171–21176, 2025. doi: 10.48084/etasr.10072.
M. Fahim, F. Alam, H. Khan, I. U. Haq, S. Ullah, and S. Zaman, “The behavior of RC beams retrofitted with carbon fiber reinforced polymers (CFRP),” Eng. Technol. Appl. Sci. Res., vol. 12, no. 3, pp. 8701–8706, 2022. doi: 10.48084/etasr.4926.
A. Yahya Turki and M. H. Al-Farttoosi, “Investigation of the stiffness and ductility of pre-cracked RC beams after repairing with CFRP using different strengthening methods,” Eng. Technol. Appl. Sci. Res., vol. 13, no. 6, pp. 12423–12426, 2023. doi: 10.48084/etasr.6555.
H. Q. Abbas and A. H. Al-Zuhairi, “Flexural strengthening of prestressed girders with partially damaged strands using enhancement of carbon fiber laminates by end sheet anchorages,” Eng. Technol. Appl. Sci. Res., vol. 12, no. 4, pp. 8884–8890, 2022. doi: 10.48084/etasr.5007.
N. Askarizadeh and M. R. Mohammadizadeh, “Numerical analysis of carbon fiber reinforced plastic (CFRP) shear walls and steel strips under cyclic loads using finite element method,” Eng. Technol. Appl. Sci. Res., vol. 7, no. 6, pp. 2147–2155, 2017. doi: 10.48084/etasr.1279.
H. Hasan and M. H. Al-Farttoosi, “Investigation of the experimental shear resistance of RC T-beams after strengthening with carbon fiber-reinforced polymer (CFRP) bars,” Eng. Technol. Appl. Sci. Res., vol. 14, no. 1, pp. 12608–12614, 2024. doi: 10.48084/etasr.6578.
M. Zahid and S. Al-Zaidee, “Validated finite element modeling of lightweight concrete floors stiffened and strengthened with FRP,” Eng. Technol. Appl. Sci. Res., vol. 13, no. 4, pp. 11387–11392, 2023. doi: 10.48084/etasr.6055.
Z. H. Abdulghafoor and H. A. Al-Baghdadi, “Static and dynamic behavior of circularized reinforced concrete columns strengthened with hybrid CFRP,” Eng. Technol. Appl. Sci. Res., vol. 12, no. 5, pp. 9336–9341, 2022. doi: 10.48084/etasr.5162.
O. Anil, N. Kaya, and O. Arslan, “Strengthening of one-way RC slab with opening using CFRP strips,” Constr. Build. Mater., vol. 48, pp. 883–893, 2013.
M. Mahlis, A. E. Shoeib, S. Abd Elnaby, and A. Sherif, “The effect of cutting openings on the behavior of two-way solid loaded slabs,” Structures, vol. 16, pp. 137–149, 2018.
S. Aman, B. S. Mohammed, M. A. Wahab, and A. Anwar, “Performance of reinforced concrete slab with opening strengthened using CFRP,” Fibers, vol. 8, no. 4, p. 25, 2020.
M. A. El-Mandouh, M. S. Omar, and A. S. Abd El-Maula, “Behaviour of RC flat slabs with openings strengthened with CFRP,” Case Stud. Constr. Mater., vol. 15, 2021. doi: 10.1016/j.cscm.2021.e00587.
L. Turanli, T. Ozturan, and U. Ersoy, “Strengthening of reinforced concrete slabs with FRP laminates using self-compacting concrete,” Constr. Build. Mater., vol. 22, no. 5, pp. 961–971, 2008.
F. Bencardino and A. Condello, “Behavior of CFRP strengthened self-compacting concrete slabs,” Compos. Struct., vol. 152, pp. 529–539, 2016.
H. M. Elsanadedy, T. H. Almusallam, S. H. Alsayed, and Y. A. Al-Salloum, “Punching shear performance of CFRP-strengthened SCC slabs,” Eng. Struct., vol. 205, p. 110084, 2020.
Central Organization for Standardization and Quality Control, Iraqi Specification No. 5/1984: Portland Cement. Baghdad, Iraq, 1984.
Central Organization for Standardization and Quality Control, Iraqi Specification No. 45/1984: Portland Cement. Baghdad, Iraq, 1984.
ASTM International, ASTM A615/A615M-23: Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement. West Conshohocken, PA, USA, 2023.
ACI (American Concrete Institute), Building Code Requirements for Structural Concrete and Commentary, ACI 318. Farmington Hills, MI, 2019.