Title:
Bond Behaviour of CFRP Bars Prestressed in Self-Consolidating Concrete Beams
Author(s):
Slamah S. Krem and Khaled A. Soudki
Publication:
Symposium Paper
Volume:
327
Issue:
Appears on pages(s):
36.1-36.20
Keywords:
CFRP, prestressed beams, self-consolidating concrete, transfer and development lengths
DOI:
10.14359/51713357
Date:
11/1/2018
Abstract:
Self-consolidating concrete (SCC) is an emerging technology that provides improved productivity and quality of concrete construction. The current ACI 440.4R-04 design guideline does not account for SCC in the calculation of the transfer and development lengths of prestressed CFRP bars. Recent developments in the FRP bar manufacturing process can significantly affect the bond behavior of FRP bars in concrete. This paper presents measurements from 16 beams prestressed with 12.7 mm (½̏) CFRP bars. Transfer length was determined through longitudinal concrete strain profile and draw-in measurements, and development length was determined by flexural tests. The results revealed a nonlinear variation in the transfer length of CFRP bars in SCC versus the prestressing level. Prediction of the transfer and development length predictions for the 12.7 mm (½̏) CFRP bar based on ACI 440.4R-04 are unconservative when the prestressing level exceeds 750 MPa (110 ksi). The paper proposes a modification to the existing ACI 440.4R-04 equation to account for SCC. At a 90 % confidence interval, the test results show an average deviation of ± 8 % for the proposed model.
Related References:
ACI Committee 237 (2007), “Self-Consolidating Concrete,” ACI 237R-07, American Concrete Institute, Farmington Hills, MI, USA.
ACI Committee 440 (2004), “Pre-stressing Concrete Structures with FRP Tendons,” ACI 440.4R-04, American Concrete Institute, Farmington Hills, MI.
Burgueno, R., and Haq, M. (2007), “Effect of SCC Mixture Proportioning on Transfer and Development Length of Prestressing Strand,” American Concrete Institute, SP- 247-9, 105-116.
Domenico, N., Mahmoud, Z., and Rizkalla, S. (1998), “Bond Properties of Carbon Fiber Composite Prestressing Strands,” ACI Str. J., 95(3), 281-290.
Girgis, A., and Tuan, C., (2005). “Bond Strength and Transfer Length of Pretensioned Bridge Girders Cast with Self-Consolidating Concrete.” PCI Journal 50(6), 72-87.
ISIS Canada (2008). “Prestressing Concrete Structures with Fiber Reinforced Polymers.” Design Manual No. 5, Winnipeg, Manitoba, Canada.
Janney, J. (1954). “Nature of Bond in Pretensioned Concrete.” ACI Journal, 25(9), 717-736.
Khayat, K., and Mitchell, D., (2009). “Self-Consolidating Concrete for Precast, Prestressed Concrete Bridge Elements.” NCHRP report 628, Transportation Research Board, Washington, D.C. USA.
Krem, Slamah, (2013) “Bond and flexural behaviour of self-consolidating concrete beams reinforced and prestressed with FRP bars”, Doctoral dissertation, University of Waterloo
Logan, D., (1997), “Acceptance Criteria for Bond Quality of Strand for Pretensioned Prestressed Concrete Applications,” PCI J., 42(2), 52-90.
Mahmoud, Z., Rizkalla, S., and Zaghloul, E., (1999), “Transfer and Development Lengths of Carbon Fiber Reinforced Polymers Prestressing Reinforcement,” ACI Str. J., 96(4), 594- 602.
Marti-Vargas, J., Arbelaez, C., Serna-Ros, P., and Castro-Bugallo, C. (2007). “Reliability of Transfer Length Estimation from Strand End Slip.” ACI Structural Journal, 104(4), 487-494.
Naito, C., Parent, G. and Brunn, G. (2006). “Performance of Bulb-Tee Girders Made with Self-Consolidating Concrete.” PCI Journal, 51(6), 72-85.
Pozolo, A. M., and Andrawes, B. (2011). “Transfer length in Prestressed Self-Consolidating Concrete Box and I-Girders.” ACI Structural Journal, 108(3), 341-349.
Russell, B., and Burns, N. (1996). “Measured Transfer Length of 0.5 and 0.6 in Strands in Pretensioned Concrete.” PCI Journal, 41(5), 44-65.
Schindler, A. et al., (2007), “Properties of Self-Consolidating Concrete for Prestressed members,” ACI Mat. J., 104(1), 53-61.
Soudki, K. (2010). “Tensile Capacity of CFRP V-Rod Bars.” Technical Report, University of Waterloo, Waterloo, Ontario, (May 3rd 2010).
Taerwe, L., and Pallemans, I. (1995). “Force Transfer of AFRP Bars in Concrete Prisms.” Proc., .2nd Int. Symp.on Non-metallic (FRP) Reinforcement for Concrete Structures, RILEM, Ghent, Belgium, 54-163.
Vilanova, A., Fernández-Gómez, J., and Landsberger G., (2012), “Mechanical Properties of Self-Consolidating Concrete Using Conventional Concrete Models,” ACT Str. J., 109(6) 587-596.
Zou, P. (2003). “Long-Term Properties and Transfer Length of Fiber-Reinforced Polymers.” Journal of Composites for Construction, 7(1), 10-19.