Steel–CFRP Composite (CFRP Laminate Sandwiched between Mild Steel Strips) and It-s Behavior as Stirrup in Beams

In this present study, experimental work was conducted to study the effectiveness of newly innovated steel-CFRP composite (CFRP laminates sandwiched between two steel strips) as stirrups. A total numbers of eight concrete beams were tested under four point loads. Each beam measured 1600 mm long, 160mm width and 240 mm depth. The beams were reinforced with different shear reinforcements; one without stirrups, one with steel stirrups and six with different types and numbers of steel-CRFR stirrups. Test results indicated that the steel-CFRP stirrups had enhanced the shear strength capacity of beams. Moreover, the tests revealed that steel- CFRP stirrups reached to their ultimate tensile strength unlike FRP stirrups which rupture at much lower level than their ultimate strength as werereported in various researches.




References:
[1] ACI 440.4R-04(2004), "Prestressing concrete structures with FRP
tendons", Farmington Hills, Mich.
[2] ACI 440.1R-06. (2006). "Guide for the design and construction of
structural concrete reinforced with FRP bars." Farmington Hills, Mich.
[3] ACI-ASCE Joint Committee 445. (1998), "Recent approaches to shear
design of structural concrete" Journal of structure Engineering 124(12),
1375- 1417.
[4] Ahmed K. El-Sayed, Ehab El-Salakawy and Brahim Benmokrane,
(2007), "Characterization of New Carbon FRP Stirrups for Concrete
Members" Journal of Composites for Construction, Vol. 11, No.4.
[5] Chadon Lee, P.E. Jun-Yeop Kim and Seo-Young Heo, (2010)
"Experimental Observation on the Effectiveness of Fibre Sheet Strip
Stirrups in Concrete Beams" Journal of Composites for Construction,
Vol. 14, No. 5, October 1, 2010.
[6] Shehata, E., Morphy, R., and Rizkalla, S. (1998),"Use of FRP as shear
reinforcement for concrete structures" Second international concrete on
composites in infrastructure, Edited by Saadatmanesh and M. R.
Ehsanim, ISIS Canada, University of Manitoba, Winnipeg, Manitoba,
Canada, 300-314.
[7] Ehsani, M. R., Saadatmanesh, H., and Tao, S. (1995),"Bond of hooked
glass fibre reinforced plastic (GFRP)reinforcing bars to concrete."ACI
Material Journal, 92 (4), 391-400.
[8] Faris Abbas Jawad Uraiyer, "The new Steel-CFRP composite specimen
(CFRP laminates sandwiched between two steel strips) and its behaviour
under Uniaxial tension" International Journal of Civil and Structural
Engineering, Volume 3, No 1, 2012.
[9] Fam, A. Z., Rizkalla, S. H., and Tadros, G. (1997), "Behaviour of CFRP
for prestressing and shear reinforcements of concrete high way bridges."
ACI Structural Journal, 94(1), 77-86.