Performance And Failure Behavior Of Prestressed Concrete Beams Strengthened With Multi-Layer CFRP: Experimental And Numerical Investigation

Hayder Abdul Hadi Abdul Razzaq

doi:10.29284/1cv7k425

Authors

Hayder Abdul Hadi Abdul Razzaq PhD in structural engineering, A' Lecturer in Islamic University Al-Najaf, College of Engineering Technology, Department of Building and Construction Technology

DOI:

https://doi.org/10.29284/1cv7k425

Keywords:

Prestressed Concrete, CFRP Strengthening, Flexural Behaviour, Ductility, Debonding, Sustainability, Environmental Impact.

Abstract

This study presents a comprehensive experimental and analytical investigation into the flexural behavior and sustainability implications of reinforced prestressed concrete (PC) beams strengthened externally with Carbon Fiber Reinforced Polymer (CFRP) laminates. The research aimed to evaluate the synergistic effects of varying prestressing force levels (150 kN and 200 kN) and the number of CFRP layers (one, two, and three) on structural performance and long-term durability. Seven full-scale beams were tested under a four-point bending setup. The results demonstrate that CFRP strengthening significantly enhanced the ultimate load-carrying capacity. The experimental work shown increases ranging from 35% to 106.4% compared to the unstrengthened control beam. A corresponding rise in post-cracking flexural stiffness was also observed. However, this substantial gain in strength was accompanied by a significant reduction in ductility, shifting the failure mode from ductile concrete crushing in the control beam to brittle CFRP rupture and interfacial debonding. CFRP strengthening contributes positively to sustainability as it uses less material, reduces the frequency of maintenance, extends the service life of the structure, and decreases carbon emissions compared to conventional retrofitting. Apart from addressing the fundamental trade-off between strength and ductility, the research highlights that further refinements in the application of CFRP will enhance structural efficiency and improve the sustainability of building designs.

References

[1] Alkurdi, N. (2021). Flexural behaviour of enhanced foamed concrete beams reinforced with GFRP bars (Master’s thesis, Nottingham Trent University). https://www.researchgate.net/profile/Nadir-Alkurdi.

[2] Covatariu, D., Filip, A., & Covatariu, G. (2024). Computational assessment regarding structural rehabilitation of a reinforced concrete decanter tank. IOP Conference Series: Materials Science and Engineering, 1304(1), 012018. https://doi.org/10.1088/1757-899X/1304/1/012018.

[3] El Baky, H. A. (2008). Nonlinear micromechanics-based finite element analysis of the interfacial behaviour of FRP-strengthened reinforced concrete beams (Doctoral dissertation, Université de Sherbrooke).

[4] El Gendy, M., El Arabi, I., Elbarbary, A., & Hamed, M. (2025). Comparative study of structural behaviour of CFRP tubes and traditional steel for pile and column applications, in compliance with international codes. Discover Civil Engineering, 2(1), 1–33. https://doi.org/10.1007/s44290-025-00244-6.

[5] Elharouney, B. H., Hussein, A., Mostafa, E. E. D., & Elnemr, A. (2019). Flexural behaviour of prestressed concrete beams strengthened by near-surface-mounted FRP rods. Journal of Al-Azhar University Engineering Sector, 14(53), 1424–1435. https://doi.org/10.21608/AUEJ.2019.64241.

[6] Garg, S., Matsagar, V., & Marburg, S. (2023). Nonlinear finite element analyses of prestressed concrete beams strengthened with CFRP laminate. Structural Engineering International, 33(2), 258–264. https://doi.org/10.1080/10168664.2022.2158449.

[7] Gupta, C., Arora, H. C., Kumar, A., Kumar, P., Kapoor, N. R., & Sharma, M. (2024). Axial capacity estimation of FRP-strengthened corroded concrete columns. Journal of Soft Computing in Civil Engineering, 8(4), 160–185. https://doi.org/10.22115/scce.2024.414586.1708.

[8] Hassas, N., & Bordbar, A. T. (2025). Investigating the problems of historical buildings in relation to earthquakes and researching some of their retrofitting methods. Budownictwo i Architektura, 24(1), 75–95. https://doi.org/10.35784/bud-arch.6519.

[9] Hu, Z., Elchalakani, M., Yehia, S., Ran, H., Sadakkathulla, M. A., & Guo, X. (2024). Engineered cementitious composite (ECC) strengthening of reinforced concrete structures: A state-of-the-art review. Journal of Building Engineering, 86(1), Article 108941. https://doi.org/10.1016/j.jobe.2024.108941.

[10] Huang, J. (2019). Structural performance of precast reinforced geopolymer concrete sandwich panels enabled by FRP connectors (Doctoral dissertation, The Hong Kong Polytechnic University). https://theses.lib.polyu.edu.hk/handle/200/10015.

[11] Işıklı, Y. (2025). Strut and tie modelling of reinforced concrete structures with dual-system optimisation. (Doctoral dissertation, Middle East Technical University). https://open.metu.edu.tr/handle/11511/113997.

[12] Jin, L., Li, X., Zhang, R., & Du, X. (2024). Failure mechanism and dynamic response of reinforced concrete joints under impact load acting on beam ends. International Journal of Impact Engineering, 185, Article 104863. https://doi.org/10.1016/j.ijimpeng.2023.104863.

[13] Khan, W., Akhtar, S., Rawat, A., & Basu, A. (2024). Experimental and numerical study on flexural behaviour of concrete beams with notch and repairing materials. Sustainability, March 2024, 16(7), Article 2723, https://doi.org/10.3390/su.16072723.

[14] Koura, M. M., Tahwia, A. M., & Matthana, M. H. (2024). Influence of macro-synthetic fibres on the flexural behaviour of high-strength concrete beams reinforced with GFRP bars. Mansoura Engineering Journal, 49(4), 1–12. https://doi.org/10.58491/2735-4202.3205.

[15] Liu, S., Wang, X., Ali, Y., Huang, H., & Wu, Z. (2024). Evaluation of deflection calculation for hybrid-reinforced concrete with fibre-reinforced polymer and steel bars. ACI Structural Journal, 121(4). https://doi.org/10.14359/51740717.

[16] Mansour, W., Osama, B., Li, W., Wang, P., & Sobuz, M. H. R. (2024). Numerical response of concrete-filled steel tubular (CFST) columns externally strengthened with FRP composites subjected to cyclic loading. International Journal of Concrete Structures and Materials, 18(1), Article 82. https://doi.org/10.1186/s40069-024-00716-6.

[17] Mazaheripour, H. (2015). Structural behaviour of hybrid GFRP and steel reinforced FRC prestressed beams (Doctoral dissertation, Universidade do Minho). https://hdl.handle.net/1822/41858.

[18] Montaser, W. M., Shaaban, I. G., Zaher, A. H., Khan, S. U., & Sayed, M. N. (2022). Structural behaviour of polystyrene foam lightweight concrete beams strengthened with FRP laminates. International Journal of Concrete Structures and Materials, 16(1), Article 59. https://doi.org/10.1186/s40069-022-0059-x.

[19] Näsbom, A., Thoma, K., & Kaufmann, W. (2024). Construction and testing of a CFRP-prestressed railway bridge prototype. IABSE Symposium Report, 90–98. https://doi.org/10.2749/manchester.2024.0090.

[20] Noël, M. (2013). Behaviour of post-tensioned slab bridges with FRP reinforcement under monotonic and fatigue loading (Doctoral dissertation, Waterloo University, Canada). https://hdl.handle.net/10012/647.

[21] O’Hegarty, R., Kinnane, O., Grimes, M., Newell, J., Clifford, M., & West, R. (2021). Development of thin precast concrete sandwich panels: Challenges and outcomes. Construction and Building Materials, 267, Article 120981. https://doi.org/10.1016/j.conbuildmat.2020.120981.

[22] Sah, T. P., Lacey, A. W., Hao, H., & Chen, W. (2024). Prefabricated concrete sandwich and other lightweight wall panels for sustainable building construction: State-of-the-art review. Journal of Building Engineering, 89, Article 109391. https://doi.org/10.1016/j.jobe.2024.109391.

[23] Shi, J., Wang, H., & Cao, X. (2024). Mechanical behaviour and innovative applications of fibre-reinforced cementitious composite and fibre-reinforced polymer in infrastructures. Buildings, 14(12), Article 3993. https://doi.org/10.3390/buildings14123993.

[24] Tayfur, S., Alver, N., Türk, E., Menteşoğlu, M., & Ercan, E. (2024). Failure behaviour of CFRP-strengthened reinforced concrete beam–column joints under reversed-cyclic lateral loading: Mechanical and acoustic emission observations. Structural Engineering International, 34(1), 141–152. https://doi.org/10.1080/10168664.2022.2164237.

[25] Wang, K. (2025). Study on a comprehensive evaluation and decision-making method for all-composite bridge structure design scheme. Advances in Mechanical Engineering, 17(2), 1-13. https://doi.org/10.1177/16878132251319676.

[26] Wang, X., Li, Y., Wu, S., Li, R., Tian, C., Hou, Q., & Long, F. (2022). Seismic performance of a novel partly precast RC shear wall with double precast edge members and a central T-shape CIP member. Soil Dynamics and Earthquake Engineering, 162, Article 107481. https://doi.org/10.1016/j.soildyn.2022.107481.

[27] Yuan, X., Gong, Z., Bai, H., Sun, C., & Shi, L. (Dec. 2024). Flexural behavior of concrete members reinforced with carbon–glass fiber composite plate based on mechanical anchoring. Structural Engineering International, 35(1), 1–13. https://doi.org/10.1080/10168664.2024.2425074.