EXPERIMENTAL INVESTIGATION OF FLEXURAL PERFORMANCE OF T-SHAPED HYBRID CONCRETE BEAMS RETROFITTED WITH NSM TECHNIQUE USING GFRP BARS

Meqdam Y. Y.  Al-Jabban; Haider A. A.  Al-Katib

doi:10.30572/2018/KJE/170121

Authors

Eng. Meqdam Y. Y. Al-Jabban MSc. Student, Department of Civil Engineering, Engineering Faculty, University of Kufa, Najaf, Iraq
Prof. Dr. Haider A. A. Al-Katib Prof. Dr., Department of Civil Engineering, Engineering Faculty, University of Kufa, Najaf, Iraq

DOI:

https://doi.org/10.30572/2018/KJE/170121

Keywords:

Retrofitting, T-Beam, Hybrid Concrete, Self-Compacting High Strength Concrete, Flexural Behavior, Near-Surface Mounting Technique, Glass Fiber Reinforced Polymer Bars

Abstract

In this research, thirteen T-shaped hybrid concrete beams were designed to investigate their flexural behavior. Flanges of all beams were cast by 106 N/mm² f_cu of self-compacting high-strength concrete (SC-HSC), while the webs were made by 45 N/mm² f_cu of normal-strength concrete (NSC). One beam was loaded up to failure as a control beam (CB), and the other beams were divided into two groups; the first group consisted of six beams preloaded by 45% of CB's ultimate load (P_u), and the other group of beams subjected to 85% of CB's P_u. Beams were retrofitted along the entire clear span using various numbers and placements of glass fiber-reinforced polymer (GFRP) bars mounted near the bottoms and side(s) surfaces. However, tests resulted in a notable enhancement ranging from 35% to 101% of retrofitted beams. At the same time, the maximum deflections of both groups witnessed a range from 21.9 mm to 34.9 mm beside CB's ultimate deflection (33.8 mm); in addition, ductility ratio, toughness, and stiffness values varied between (55.89% and 73.8% reduction), (15.95% decrement and 31.96% increment), and (2.36% and 47.83% reduction), respectively. Furthermore, the failure mode was mainly GFRP-Epoxy debonding

Downloads

Download data is not yet available.

References

Al Shami, A.M.H. (2022) Shear behavior of hybrid tee section concrete beams with openings and strengthened by CFRP laminates. Master's dissertation, Faculty of Engineering, University of Kufa, Iraq.

Al Thairy, H. and Youssef, A.J. (2023) ‘Flexural and shear behaviour of lightweight RC beams strengthened by NSM GFRP bars’, Journal of Building Pathology and Rehabilitation, 8, Article number: 31. Available at: https://doi.org/10.1007/s41024-023-00276-4. DOI: https://doi.org/10.1007/s41024-023-00276-4

Al-Hilfi, A.L.A. and Al-Katib, H.A.A. (2024) ‘Retrofitting of hybrid concrete beams in shear using externally bonded CFRP sheets’, The 5th International Conference on Civil and Environmental Engineering Technologies, AIP Conference Proceedings, 3249, pp. 020012-1–020012-18. Available at: https://doi.org/10.1063/5.0236561. DOI: https://doi.org/10.1063/5.0236562

Aljebory, S.M. and Kamonna, H.H. (2025) ‘Repairing of continuous one-way reinforced concrete slabs by CFRP composites’, Kufa Journal of Engineering, 16(1), pp. 324–343. Available at: https://doi.org/10.30572/2018/KJE/160119. DOI: https://doi.org/10.30572/2018/KJE/160119

Al-Katib, H.A.A. and AL-Turaihi, A.A.A. (2024) ‘Behavior of hybrid reinforced concrete beams on flexural strength’, Kufa Journal of Engineering, 15(2), pp. 27–38. Available at: https://doi.org/10.30572/2018/KJE/150203. DOI: https://doi.org/10.30572/2018/KJE/150203

Al-Katib, H.A.A. and AL-Turaihi, A.A.A. (2024) ‘Effect of GFRP bar length on the flexural behavior of hybrid concrete beams strengthened with NSM bars’, Open Engineering. Available at: https://doi.org/10.1515/eng-2022-0538. DOI: https://doi.org/10.1515/eng-2022-0538

American Concrete Institute (2017) ACI 440.2R-17: Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. ACI Committee 440.

American Concrete Institute (2019) ACI CODE-318-19: Building code requirements for structural concrete and commentary. ACI Committee 318.

ASTM International (2024) ASTM A615/A615M-24: Standard specification for deformed and plain carbon steel bars for concrete reinforcement. West Conshohocken, PA. Available at: https://doi.org/10.1520/A0615_A0615M-24. DOI: https://doi.org/10.1520/A0615_A0615M-24

BenSaoud, M., Oraf, M., Gundogay, A., Yaman, S., Eren, V. and Kabas, H.T. (2024) ‘An experimental study on repairing of reinforced concrete beams having damaged longitudinal bars’, Applied Sciences, 14(23), Article number: 11310. Available at: https://doi.org/10.3390/app142311310. DOI: https://doi.org/10.3390/app142311310

Hosen, M.A., Alengaram, U.J., Jumaat, M.Z., Sulong, N.H.R. and Darain, K.M. (2017) ‘Glass fiber reinforced polymer (GFRP) bars for enhancing the flexural performance of RC beams using side-NSM technique’, Polymers, 9(5), p.180. Available at: https://doi.org/10.3390/polym9050180. DOI: https://doi.org/10.3390/polym9050180

Hosen, M.A., Jumaat, M.Z., Alsubari, B., Sulong, N.H.R., Ibrahim, Z., Alengaram, U.J. and Hashim, H. (2020) ‘Effect of bonding materials on the flexural improvement in RC beams strengthened with SNSM technique using GFRP bars’, Journal of Building Engineering, 32, 101777. Available at: https://doi.org/10.1016/j.jobe.2020.101777. DOI: https://doi.org/10.1016/j.jobe.2020.101777

Joudah, R.S. and Al-Katib, H.A.A. (2024) ‘Flexural behavior for repairing of hybrid concrete beams by NSM-GFRP bars’, The 5th International Conference on Civil and Environmental Engineering Technologies, AIP Conference Proceedings, 3249, pp. 020016-1–020016-15. Available at: https://doi.org/10.1063/5.0237250. DOI: https://doi.org/10.1063/5.0237250

Kamonna, H.H. and Abd Al-Sada, D.J. (2021) ‘Effect of near-surface mounted bars on the structural behavior of one-way RC slab’, Kufa Journal of Engineering, 12(3), pp. 12–30. Available at: http://dx.doi.org/10.30572/2018/KJE/120302. DOI: https://doi.org/10.30572/2018/kje/120302

Marzoq, Z.H. and Borhan, T.M. (2020) ‘The behaviour of hybrid reinforced concrete T beams exposed to the flexural moment’, Asian Journal of Civil Engineering, 21, pp. 1005–1012. Available at: https://doi.org/10.1007/s42107-020-00257-9. DOI: https://doi.org/10.1007/s42107-020-00257-9

Reda, R.M., Sharaky, I.A., Ghanem, M., Seleem, M.H. and Sallam, H.E.M. (2016) ‘Flexural behavior of RC beams strengthened by NSM GFRP bars having different end conditions’, Composite Structures, 147, pp. 131–142. Available at: https://doi.org/10.1016/j.compstruct.2016.03.018. DOI: https://doi.org/10.1016/j.compstruct.2016.03.018

Sharaky, I.A., Torres, L., Comas, J. and Barris, C. (2014) ‘Flexural response of reinforced concrete (RC) beams strengthened with near surface mounted (NSM) fibre reinforced polymer (FRP) bars’, Composite Structures, 109, pp. 8–22. Available at: https://doi.org/10.1016/j.compstruct.2013.10.051. DOI: https://doi.org/10.1016/j.compstruct.2013.10.051

Tahmouresi, B., Momeninejad, K. and Mohseni, E.E. (2022) ‘Flexural response of FRP strengthened lightweight RC beams: hybrid bond efficiency of L‐shape ribbed bars and NSM technique’, Archives of Civil and Mechanical Engineering, 22, Article number: 95. Available at: https://doi.org/10.1007/s43452-022-00410-y. DOI: https://doi.org/10.1007/s43452-022-00410-y

Tang, W.C., Balendran, R.V., Nadeem, A. and Leung, H.Y. (2006) ‘Flexural strengthening of reinforced lightweight polystyrene aggregate concrete beams with near-surface mounted GFRP bars’, Building and Environment, 41(10), pp. 1381–1393. Available at: https://doi.org/10.1016/j.buildenv.2005.05.029. DOI: https://doi.org/10.1016/j.buildenv.2005.05.029