Enhancing Torsional Behavior of Deep Beams Strengthened with NSM Steel and Basalt Bars under Repeated Pure Torsion
Corresponding author: Noor M. Salih
Abstract
This study investigates the torsional behavior of reinforced concrete deep beams enhanced through the Near-Surface Method (NSM), using steel and basalt bars under repeated torsional loads. Five beam specimens were cast and tested. One served as the unstrengthened reference, while the remaining four were reinforced using NSM bars on either two or four sides. The experimental program investigated the impact of reinforcing material (steel and basalt) and several strengthened faces. The results demonstrated that the NSM strengthening significantly enhanced the beams’ torsional resistance. When evaluated with the reference beam, the ultimate torque increased by 16.5% and 30.4% for the two-sided and four-sided steel structures, respectively, while the basalt bars exhibited enhancements of 33.0% and 46.0%, respectively. Furthermore, the longitudinal elongation at failure decreased by as much as 22.3% in the most effective configurations, indicating a significant enhancement in the deformation control. The study indicates that augmenting the number of reinforced faces and employing basalt bars achieves beneficial results in terms of strength and stiffness.
Keywords:
deep beam, pure torsion, NSM strengthening, basalt bar, repeated loadsDownloads
References
Building Code Requirements for Structural Concrete and Commentary, ACI 318-19, American Concrete Institute, Farmington Hills, MI, 2019.
ACI Committee 408, State-of-the-Art Report: Bond under Cyclic Loads, 6th ed., vol. 88. Farmington Hills, MI: American Concrete Institute, 1992.
G. Al-Bayati, R. Al-Mahaidi, and R. Kalfat, "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, vol. 124, pp. 1153–1164, Oct. 2016.
G. Al-Bayati, R. Al-Mahaidi, and R. Kalfat, "Torsional strengthening of reinforced concrete beams using different configurations of NSM FRP with epoxy resins and cement-based adhesives," Composite Structures, vol. 168, pp. 569–581, May 2017.
K. F. K. Hassanien, "Strengthening of reinforced concrete beams using near-surface mounted FRP," International Journal of Engineering Science and Innovative Technology, vol. 4, no. 5, pp. 231–237, Sep. 2015.
K. N. Rahal and H. A. Rumaih, "Tests on reinforced concrete beams strengthened in shear using near surface mounted CFRP and steel bars," Engineering Structures, vol. 33, no. 1, pp. 53–62, Jan. 2011.
A. A. Abdul Samad, D. R. Hassen, N. Mohamad, A. N. Attiyah, J. Jayaprakash, and P. Mendis, "Shear Rehabilitation of RC Deep Beams using NSM CFRP Anchor Bars," MATEC Web of Conferences, vol. 103, 2017, Art. no. 02010.
M. A. Anis A. and M. Thaer Matlab, "Shear Strengthening of RC without Stirrups for Deep Beams with Near Surface Mounted CFRP Rods," International Journal of Engineering Research & Technology, vol. 04, no. 06, pp. 545–547, Jun. 2015.
F. Elgabbas, E. A. Ahmed, and B. Benmokrane, "Physical and mechanical characteristics of new basalt-FRP bars for reinforcing concrete structures," Construction and Building Materials, vol. 95, pp. 623–635, Oct. 2015.
A. Serbescu, M. Guadagnini, and K. Pilakoutas, "Mechanical Characterization of Basalt FRP Rebars and Long-Term Strength Predictive Model," Journal of Composites for Construction, vol. 19, no. 2, Apr. 2015, Art. no. 04014037.
C. C. Gowda, J. A. O. Barros, and M. Guadagnini, "Experimental study of torsional strengthening on thin walled tubular reinforced concrete structures using NSM-CFRP laminates," Composite Structures, vol. 208, pp. 585–599, Jan. 2019.
N. Habeeb Askandar and A. Darweesh Mahmood, "Torsional Strengthening of RC Beams with Near‐Surface Mounted Steel Bars," Advances in Materials Science and Engineering, vol. 2020, no. 1, Jan. 2020, Art. no. 1492980.
M. Alrawi and M. Mahmood, "Strengthening Reinforced Beams Subjected to Pure Torsion by Near Surface Mounted Rebars," Anbar Journal for Engineering Sciences, vol. 13, no. 1, pp. 13–22, Oct. 2022.
M. I. Ali and A. A. Al-Azzawi, "Finite element analysis of RC beams strengthened with near-surface mounted reinforcement bars under pure torsion," IOP Conference Series: Earth and Environmental Science, vol. 1232, no. 1, Sep. 2023, Art. no. 012026.
Portland Cement, Specifications No. 5, Iraqi specifications, Baghdad, Iraq, 1984.
Specification for Portland Cement, ASTM C150/C150M-22, ASTM International, West Conshohocken, PA, 2022.
Aggregate from Natural Sources for Concrete and Construction, Specifications No. 45, Iraqi Specifications, Baghdad, Iraq, 1984.
Testing concrete, BS 1881-116:1983 British Standards Institution, London, Jan. 1983.
Standard Test Method for Flexural Strength of Concrete (Using Simple Beam With Center-Point Loading), ASTM C293/C293M-16 ASTM International, West Conshohocken, PA, 2016.
Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens, ASTM C496/C496M-17 ASTM International, West Conshohocken, PA, 2017.
S. B. Kadhum and A. H. Al-Zuhairi, "The Effect of Construction Joints on the Behavior of Reinforced Concrete Deep Beams," Engineering, Technology & Applied Science Research, vol. 14, no. 4, pp. 16083–16089, Aug. 2024.
A. A. Elghany, M. Elsayed, A. Elsayed, and A. Shaheen, "Enhancement of the Shear Capacity of RC Deep Beams with Ultra-High Performance Fiber-reinforced Concrete," Engineering, Technology & Applied Science Research, vol. 15, no. 1, pp. 20418–20424, Feb. 2025.
N. H. Askandar and A. D. Mahmood, "Torsional Strengthening of RC Beams with Continuous Spiral Near-Surface Mounted Steel Wire Rope," International Journal of Concrete Structures and Materials, vol. 14, no. 1, Dec. 2020, Art. no. 7.
M. I. Ali and A. A. Al-Azzawi, "Finite element analysis of RC beams strengthened with near-surface mounted reinforcement bars under pure torsion," IOP Conference Series: Earth and Environmental Science, vol. 1232, no. 1, Sep. 2023, Art. no. 012026.
S. F. M. Razak, M. A. Ahmad, A. A. A. Samad, and M. A. Alqurashi, "Strengthening of RC beams subjected to pure torsion using near surface mounted (NSM) CFRP bars," Journal of Engineering Science and Technology, vol. 17, no. 3, pp. 2059–2076, Jun. 2022.
A. M. Rteil and F. F. Haddad, "Torsional behavior of high-strength concrete beams," Engineering Structures, vol. 19, no. 11, pp. 936–945, Nov. 1997.
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