Title:
The Effect of Bond on the Behavior of GFRP Reinforced Deep Beams
Author(s):
Taylor Brodbeck, Giorgio T. Proestos, and Rudolf Seracino
Publication:
Symposium Paper
Volume:
365
Issue:
Appears on pages(s):
135-147
Keywords:
fiber-reinforced polymer (GFRP)
DOI:
10.14359/51746688
Date:
3/1/2025
Abstract:
As glass fiber-reinforced polymer (GFRP) reinforcing bars become more widely used, there is a need to better understand the behavior of GFRP reinforced members. GFRP reinforced deep beams are one example of concrete members that are not currently well understood. Besides the linear elastic behavior of GFRP material, another significant difference between GFRP and steel reinforcement is the difference in surface treatment. While deformation requirements are prescribed for steel reinforcing bars, FRP bars may have different surface treatments depending on the manufacturer. The different surface treatments lead to different bond characteristics and, ultimately, a difference in performance. This research explores the effect of bond through both an analytical study using VecTor2 and a series of large-scale deep beam tests reinforced with GFRP bars. Analytically, VecTor2 was able to capture the behavior of published experiments from the literature, reinforced with sand-coated GFRP bars. An alternative surface preparation consisting of machined indentations was introduced as a parameter in this study, resulting in significant changes in the performance and behavior of the deep beams. VecTor2 was also able to capture the behavior of these beams when adjustments were made to the bond model to match the observations of the experiments.
Related References:
ACI Code Committee 318. (2019). Building Code Requirements for Reinforced Concrete (ACI 318-19) and Commentary. Farmington Hills: American Concrete Institute.
ACI Code Committee 440. (2022). Building Code Requirements for Structural Concrete Reinforced with Glass Fiber-Reinforced Polymer (GFRP) Bars – Code and Commentary (ACI 440.11-22). Farmington Hills:
American Concrete Institute.
Andermatt, M. F., Lubell, A. S. (2013). “Behavior of Concrete Deep Beams Reinforced with Internal Fiber-Reinforced Polymer—Experimental Study,” ACI Structural Journal, V. 110, No. 4, Jul.-Aug. pp. 585-594.
Collins, M. P., Mitchell. D. (1991). Prestressed Concrete Structures, Prentice Hall: Englewood Cliffs, NJ.
CSA Committee A23.3 (2019). Design of Concrete Structures, Canadian Standards Association, Mississauga, ON, Canada, 2019, 301 pp.
CSA S806 (2012) “Design and Construction of Building Structures with Fiber-Reinforced Polymers,” Canadian Standard Association, Mississauga, ON, Canada, 240 pp.
Farghaly A.S., Benmokrane B. (2013). “Shear Behavior of FRP-Reinforced Concrete Deep Beams without Web Reinforcement,” Journal of Composites for Construction, 17:040130151– 40130210.
Mohamed, K., Farghaly, A.S., Benmokrane, B. (2017). “Effect of vertical and horizontal web reinforcement on the strength and deformation of concrete deep beams reinforced with GFRP bars,” Journal of Structural
Engineering, 143:0401707901–401707914.
Nanni, A., Luca, A. D., Zadeh, J. H. (2014). Reinforced concrete with FRP Bars: Mechanics and Design. CRC Press/Taylor & Francis Group.
Vecchio, F. J. (2001). Disturbed Stress Field Model for Reinforced Concrete: Implementation. Journal of Structural Engineering, 127(1), 12-20.
Vecchio, F. J., & Collins, M. P. (1986). The Modified Compression Field Theory for Reinforced Concrete Elements Subjected to Shear. ACI Journal, 219-231.
VecTor Analysis Group. Advanced Analysis and Performance Assessment of Reinforced Concrete Structures. (n.d.). http://vectoranalysisgroup.com/