Moment Redistribution-Based Strengthening of Continuous Reinforced Concrete Slabs Using Top-Surface CFRP under Constructability Constraints
DOI:
https://doi.org/10.33474/jice.v7i1.25071Keywords:
CFRP, Constructability, Redistribution, Retrofit, StrengtheningAbstract
Functional upgrades in existing buildings often lead to increased loading demands that challenge the capacity of reinforced concrete floor systems. This study presents a strengthening strategy for a continuous one-way reinforced concrete slab subjected to a functional change from office space to an assembly area, increasing the live load from 250 kg/m² to 400 kg/m². Numerical analysis using SAP2000 indicated a significant rise in ultimate moments, rendering the existing reinforcement inadequate according to SNI 2847:2019 provisions. An initial design using externally bonded Carbon Fiber Reinforced Polymer (CFRP) at the slab soffit, following ACI 440.2R-17, was analytically sufficient to restore flexural capacity. However, constructability constraints due to a recently installed ceiling system prevented soffit intervention. To address this limitation, a redistribution-based strengthening approach was developed by installing CFRP only on the top surface of the slab. Increasing stiffness at negative moment regions modified the global force distribution, reducing positive span moments to within the existing reinforcement capacity. The findings demonstrate that force-path engineering through moment redistribution provides a practical retrofit solution for continuous slab systems with stiff supports under significant constructability constraints.
References
BSN, SNI 1727:2020, Beban Minimum untuk Perancangan Bangunan Gedung dan Struktur Lain. Jakarta Indonesia: Badan Standarisasi Nasional, 2020.
BSN, SNI 2847:2019, Persyaratan Beton Struktural untuk Bangunan Gedung. Jakarta, Indonesia: Badan Standarisasi Nasional, 2019.
P. Tworzewski and K. Bacharz, “Flexural Strengthening of Reinforced Concrete Beams Using Near-Surface Mounted (NSM) Carbon Fiber-Reinforced Polymer (CFRP) Strips with Additional Anchorage,” Materials, vol. 18, no. 11, p. 2579, May 2025, doi: 10.3390/ma18112579.
Dhafar Salam Mahdi and Hussam Ali Mohammed, “State of Art: Carbon Fiber Reinforced Concrete: A Review,” Academic International Journal of Engineering Science, vol. 2, no. 02, pp. 09–17, Nov. 2024, doi: 10.59675/E222.
E. Alsuhaibani, “Optimization of Carbon Fiber-Reinforced Polymer (CFRP) Configuration for Enhanced Flexural Performance in Strengthened Concrete Beams,” Buildings, vol. 14, no. 12, p. 3953, Dec. 2024, doi: 10.3390/buildings14123953.
I. D. G. Orlando, T. N. Bittencourt, and L. C. Meneghetti, “Reinforced concrete structures strengthened with CFRP (ACI x FIB) - Recommendations for bending design criteria,” Revista IBRACON de Estruturas e Materiais, vol. 15, no. 2, 2022, doi: 10.1590/s1983-41952022000200004.
A. Ibrahim*, S. Salem, A. Khalil, and M. El-Kateb, “Moment Redistribution in Continuous RC Beams Top Strengthened with Steel and CFRP Plates,” International Journal of Recent Technology and Engineering (IJRTE), vol. 8, no. 6, pp. 3472–3480, Mar. 2020, doi: 10.35940/ijrte.F8898.038620.
A. Mandor and A. El Refai, “Flexural response of reinforced concrete continuous beams strengthened with fiber-reinforced cementitious matrix (FRCM),” Eng. Struct., vol. 251, p. 113557, Jan. 2022, doi: 10.1016/j.engstruct.2021.113557.
A. Al-Yousuf et al., “The Behavior of Reinforced Concrete Slabs Strengthened by Different Patterns and Percentages of Carbon Fiber-Reinforced Polymer (CFRP) Plate,” Construction Materials, vol. 5, no. 2, p. 24, Apr. 2025, doi: 10.3390/constrmater5020024.
ACI Committee 440, ACI PRC-440.2-17: Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures, American Concrete Institute. American Concrete Institute, 2017.
J. G. Teng, J.-F. Chen, S. Smith, and L. Lam, “FRP-strengthened RC structures,” FRP : Strengthened RC Structures , by J. G. Teng, J. F. Chen, S. T. Smith, L. Lam, pp. 266. ISBN 0-471-48706-6. Wiley-VCH , January 2002., Jan. 2002.
C. Gui, J. Ji, C. Xu, Z. Li, and X. Guo, “Experimental and Analytical Study on the Flexural Performance of Layered ECC–Concrete Composite Beams,” Buildings, vol. 15, no. 10, p. 1592, May 2025, doi: 10.3390/buildings15101592.
N. Kotlyar, “Formulas for Beams with Semi-rigid Connections,” Engineering Journal, 1996.
H. Khoeri, S. W. Alisjahbana, J. Widjajakusuma, and N. Najid, “Estimasi Lendutan Pelat Untuk Menghitung Kapasitas Beban Dengan Akurasi Tinggi Menggunakan Uji Getar,” Konstruksia, vol. 14, no. 2, pp. 175–188, Jul. 2023, doi: 10.24853/jk.14.2.175-188.
H. M. A. Diab, T. Abdelaleem, and M. M. M. Rashwan, “Moment redistribution and flexural performance of RC continuous T-beams strengthened with NSM FRP or steel bars,” Structures, vol. 28, pp. 1516–1538, Dec. 2020, doi: 10.1016/j.istruc.2020.09.003.
H. Khoeri, “Pemilihan Metode Perbaikan dan Perkuatan Struktur Akibat Gempa (Studi Kasus pada Bank Sulteng Palu),” Konstruksia, vol. 12, no. 1, pp. 93–104, Apr. 2021, doi: 10.24853/jk.12.1.93-104.
F. H. Saeed, F. Hejazi, and R. S. M. Rashid, “Strengthening of reinforced concrete slabs using carbon fiber reinforced polymers rods and concrete jacket with a mechanical anchorage system,” Constr. Build. Mater., vol. 440, p. 137464, Aug. 2024, doi: 10.1016/j.conbuildmat.2024.137464.
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