Strengthening Reinforced Beams Subjected to Pure Torsion by Near Surface Mounted Rebars | ||
Anbar Journal of Engineering Sciences | ||
Article 2, Volume 13, Issue 1, May 2022, Pages 13-22 PDF (1.39 M) | ||
Document Type: Research Paper | ||
DOI: 10.37649/aengs.2022.175876 | ||
Authors | ||
Mashael A. Alrawi* ; Mohammad N. Mahmood | ||
Civil Engineering Department, Mosul University, Mosul, Iraq | ||
Abstract | ||
This paper investigates the possibility of strengthening Reinforced Concrete (RC) beams under pure torsion loadings. The torsional behaviour of strengthened RC beams with near-surface mounted steel and CFRP bars was investigated. The verification with the experimental work was performed to ensure the validity and accuracy which revealed a good agreement through the torque-rotation relationship, ultimate torque, and rotation, and crack pattern. This numerical study included testing of thirteen specimens (one of them was control beams while the remaining 12 were strengthened beams) with several parameters such as mounting spacing and configuration. The analytical results revealed that the addition of NSM rebar redistributed the internal stresses and enhanced the ultimate torsional strength, torque-rotation capacity, ductility, and energy absorption of the concrete beams. Most of the strengthened beams revealed the appearance of the cracks at a phase less than the reference beam by an average of (9%). Concerning the NSM strengthening, the CFRP bars provided a higher enhancement ratio when compared with the beams that strengthened with NSM steel rebar especially for the strengthening space equal to 130 mm and more. The ultimate torsional strength increased by (3.5%) and rotation decreased by (4%) approximately when the steel rebar was replaced by the carbon bar. The ductility and energy absorption of the analysed beams showed that the strengthening enhanced the ductility of the twisted beams. The ductility values varied according to the method of strengthening used, as it showed the highest values of the beam that was strengthened small spacing. | ||
Keywords | ||
RC beam; CFRP; torque; ductility; energy absorption | ||
References | ||
[1] ACI 440.2R-08. (2008). Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. Farmington Hills: American Concrete Institute.
[2] De Lorenzis, L., & Teng, J. G. (2007). Near-surface mounted FRP reinforcement: An emerging technique for strengthening structures. Composites Part B Engineering, 38, 119–143.
[3] Al-Bayati, G., Al-Mahaidi, R., & Kalfat, R. (2016). Experimental investigation into the use of NSM FRP to increase the torsional resistance of RC beams using epoxy resins and cement-based adhesives. Construction and Building Materials, 124, 1153–1164.
[4] Al-Bayati, G., Al-Mahaidi, R., Hashemi, M. J., & Kalfat, R. (2018). Torsional strengthening of RC beams using NSM CFRP rope and innovative adhesives. Composite Structures, 187, 190–202.
[5] Askandar, N., & Mahmood, A. (2019). Comparative investigation on torsional behaviour of RC beam strengthened with CFRP fabric wrapping and near-surface mounted (NSM) steel bar. Advances in Civil Engineering, 2019, 15.
[6] Nasih Habeeb Askandar1,2* and Abdulkareem Darweesh Mahmood, “Torsional Strengthening of RC Beams with Continuous Spiral Near‑Surface Mounted Steel Wire Rope., Askandar and Mahmood Int J Concr Struct Mater (2020) 14:7.
[7] Chandan C. Gowda,⁎, Joaquim A.O. Barrosa, Maurizio Guadagninib, “ Experimental study of torsional strengthening on thin walled tubular reinforced concrete structures using NSM-CFRP laminates” Composite Structures 208 (2019) 585–599.
[8] Kim, M.-J., et al. (2020). "Pure torsional behavior of RC beams in relation to the amount of torsional reinforcement and cross-sectional properties." Construction and Building Materials 260: 119801.
[9] Kachlakev D, Miller T, Yim S, Chansawat K and Potisuk T 2001 American Society for Testing and Materials Report SPR 316 (California Polytechnic State University, San Luis. Obispo, CA and Oregon State University, Corvallis OR for Oregon Department of Transportation).
[10] ACI Committee 318 2011 Building Code Requirements for Structural Concrete ACI 318M-11 and Commentary (American Concrete Institute, Farmington Hills USA) pp 155-202. | ||
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