Behavior of Reinforced Concrete Corbels Strengthened with CFRP Strips Subjected to Monotonic and Repeated Loading
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Abstract
Concrete corbels are short cantilevers subjected to monotonic and repeated loads. Repeated loads generally negatively affect the concrete structural members' strength as they decrease the resistance to external loads. To increase these loads, strengthening with carbon fiber reinforced polymer (CFRP) strips as an externally bounded technique is used. This paper studies the behavior and strength of strengthened corbels subjected to monotonic and repeated (constant and incremental) loads. The experimental program included the casting and testing of twelve double-concrete corbels. All specimens have been kept constant for corbel dimensions and main and secondary reinforcement. Nine were strengthened with CFRP strips using different patterns, while the others were left un-strengthened as control corbels. The results showed that both repeated loads' types, i.e., constant and incremental, affected the ultimate load capacity of corbels. Compared to monotonic loading, a reduction occurred in ultimate load and ultimate deflection for corbels subjected to five repeated loading cycles. For corbels strengthened by externally bounded CFRP strips under any applied loads, the ultimate load significantly increased, while the ultimate deflection decreased compared to un-strengthened at the same applied load. All corbels failed by de-bonding the CFRP strips.
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References
ACI Committee 318M-19. Building Code Requirements for Structural Concrete and Commentary (ACI 318M-19). American Concrete Institute, 2019.
Kriz LB, Raths CH. Connections in Precast Concrete Structures-Strength of Corbels. PCI Journal 1965; 10(1): 16-61. DOI: https://doi.org/10.15554/pcij.02011965.16.61
Meier U. Repair Using Advanced Composites. International Conference: Composite Construction-Conventional and Innovative 1997; Innsbruck, Austria. IABSE: p. 113-123.
Alshadidi RM, Hassan HF, Mohammed MH. Shear Behavior of High Strength Concrete Beams Reinforced with GFRP Bars and Strengthened by CFRP Sheets. Journal of Engineering and Development 2016; 20(1): 102-117.
Mohammed DH. Behavior of Reinforced Concrete Beams Strengthened by CFRP in Flexure. Ph.D. Thesis. University of Technology; Baghdad, Iraq: 2007.
David E, Djelal C, Bodin FB. Repair and Strengthening of Reinforced Concrete Beams Using Composite Materials. 2nd International PhD Symposium in Civil Engineering 1998; Budapest, Hungary.
Raoof SM, Koutas LN, Bournas DA. Textile-Reinforced Mortar (TRM) Versus Fibre-Reinforced Polymers (FRP) in Flexural Strengthening of RC Beams. Construction and Building Materials 2017; 151: 279-291. DOI: https://doi.org/10.1016/j.conbuildmat.2017.05.023
Alali SSH, Abdulrahman MB, Tayeh BA. Response of Reinforced Concrete Tapered Beams Strengthened Using NSM-CFRP Laminates. Tikrit Journal of Engineering Sciences 2022; 29(1): 99-110. DOI: https://doi.org/10.25130/tjes.29.1.08
Ashour SA, Hasanain GS, Wafa FF. Shear Behavior of High Strength Fiber Reinforced Concrete Beam. ACI Structural Journal 1992; 89(2): 176-184. DOI: https://doi.org/10.14359/2946
Almashaykhi M, Alsubari B, Abdulrahman MB, Hussein AA. Punching Strength of Reactive Powder Reinforced Concrete Flat Slabs. Tikrit Journal of Engineering Sciences 2021; 28(3): 35-47. DOI: https://doi.org/10.25130/tjes.28.3.03
Jasim IKh, Abdulrahman MB, Jomaa'h MM, Alsubari B, Abdulaali HS, Alqawzai Sh. Torsional Behavior of RC Beams with Transverse Openings Strengthened by Near Surface Mounted-Steel Wire Rope Subjected to Repeated Loading. Tikrit Journal of Engineering Sciences 2022; 29(4): 79-89. DOI: https://doi.org/10.25130/tjes.29.4.9
Mohamad-Ali AA, Attiya MA. Experimental Behavior of Reinforced Concrete Corbels Strengthened with Carbon Fibre Reinforced Polymer Strips. Basrah Journal for Engineering Science 2012; 12: 31-45.
Shadhan KK, Kadhim MMM. Use of CFRP Laminates for Strengthening of Reinforced Concrete Corbels. International Journal of Civil Engineering and Technology 2015; 6(11): 11-20.
Sayhood EK, Hassan QA, Yassin LAGh. Enhancement in the Load-Carrying Capacity of Reinforced Concrete Corbels Strengthened with CFRP Strips Under Monotonic or Repeated Loads. Engineering and Technology Journal 2016; 34(14): 2705-2719. DOI: https://doi.org/10.30684/etj.34.14A.14
Abdulrahman MB, Salih ShA, Abduljabbar RJ. The Assessment of Using CFRP to Enhance the Behavior of High Strength Reinforced Concrete Corbels. Tikrit Journal of Engineering Sciences 2021; 28(1): 71-83. DOI: https://doi.org/10.25130/tjes.28.1.08
Iraqi standard specifications No.5. Portland Cement. The Iraqi Central Organization for Standardization and Quality Control, Planning Council, Baghdad, Iraq: 1984 (in Arabic).
Iraqi standard specifications No.45. Aggregates from Natural Sources for Concrete and Building Construction. The Iraqi Central Organization for Standardization and Quality Control, Planning Council, Baghdad, Iraq: 1984 (in Arabic).
ACI Committee 211.1-91. Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete (ACI 211.1-91). American Concrete Institute, 1991.
ASTM A615/A615M-15a. Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement. American Society for Testing and Materials, 2018.
BS 1881-116. Method of Determination of Compressive Strength of Concrete Cubs. British Standards Institution, 1983.
ASTM C496/C496M. Splitting Tensile Strength of Cylindrical Concrete Specimens. American Society for Testing and Materials, 2017.
ASTM C1018. Standard Test Method for Flexural Toughness and First-Crack Strength of Fiber-Reinforced Concrete. American Society for Testing and Materials, 2018.