The effect of beam depth on the shear behavior of reinforced concrete beams externally strengthened with carbon fiber–reinforced polymer composites

Abstract

The primary objective of this article is to study the effect of beam depth on the performance of shear-deficient beams externally strengthened with carbon fiber-reinforced polymer composites. The investigated parameters include overall behavior up to failure, the onset of the cracking, crack development, and ductility. The experimental results showed that externally bonded carbon fiberreinforced polymer increased the shear capacity of the strengthened reinforced concrete beams significantly depending on the variables investigated. The use of carbon fiber-reinforced polymer composites is an effective technique to enhance the shear capacity of reinforced concrete beams. For the beams tested, as the depth of the reinforced concrete beams was increased from 225 to 450 mm which is equivalent to a/d ratio of 2.7-1.2, respectively, there was corresponding 15%-19% increase in contribution of the carbon fiber-reinforced polymer strips in terms of ultimate load. The impact of the beam depth is more pronounced on the ultimate load than the corresponding deflection of the control and strengthened beams. The results indicated that the beam depth has an influence on the angle at which primary cracking angle varied from 33, 44, 50, and 54 for beam of a/d of 2.7, 1.9, 1.5, and 1.2, respectively. If the shear crack crossed carbon fiber-reinforced polymer strips above its development length, the carbon fiber-reinforced polymer strips could not be expected to reach its ultimate strength and was thus only partially effective as observed in beams with different depths.

Shear capacity of reinforced concrete beams strengthened with web side bonded CFRP sheets

“…Khalifa et al [3] showed that strengthening using CFRP sheets increased the shear capacity of reinforced concrete beams. This phenomenon has also been reported by others [4,6,10]. However, debond of CFRP sheets from the strengthened beams due to high shear stress and occurrence of diagonal shear crack has been identified as the major problem for this strengthening system [10][11].…”

“…This phenomenon has also been reported by others [4,6,10]. However, debond of CFRP sheets from the strengthened beams due to high shear stress and occurrence of diagonal shear crack has been identified as the major problem for this strengthening system [10][11]. Bukhari et al [7] found that fiber orientation affects the ability of CFRP sheets to support shear forces.…”

“…Research reports on the application of fiberreinforced polymers began to be published in 1971 [1] and a large number of studies have been reported in recent years due to the need for new materials to retrofit structures, high-performance FRP materials and rapid development of FRP technology in the chemical industry [3][4][5][6][7][8][9][10][11][12]. Khalifa et al [3] showed that strengthening using CFRP sheets increased the shear capacity of reinforced concrete beams.…”

Shear capacity of unbonded post-tensioned concrete T-beams strengthened with CFRP and GFRP U-wraps

“…These models adopted the superposition theorem and separately considered the contributions of concrete, stirrups, and FRP sheets while the interaction between these components and the effect of the shear span-to-depth ratio were ignored. Previous studies have shown that there is an interaction between these factors in which the shear span-to-depth ratio affected the angle of inclined cracks and the deformation of FRP sheets was influenced by the bonding between the FRP sheets and concrete surface (Bousselham and Chaallal, 2006;Al-Rousan and Issa, 2016;Leung, 2015, 2017). The prestress results in more brittle behaviour in comparison with that of RC beams.…”

The Impact of Asphalt Wearing Surface Thickness on Response of Two-Span Continuous Cast-in-Place Prestressed Concrete Box Girder Highway Bridge

“…Normally, bridges are analyzed by assuming that they are instantaneously built in a time. In this analysis, real material properties should be taken into account [1][2][3][4][5][6].…”