Shear strength of reinforced concrete beams with a fiber concrete matrix

Abstract

The purpose of this study was to investigate the influence of fiber reinforcement on the shear capacity of reinforced concrete (RC) beams. Both steel and synthetic fibers at variable volume fractions were investigated. Two series of tests were performed: structural tests, where RC beams were tested to failure under an applied four-point load; and materials tests, where companion fiber-reinforced concrete (FRC) prisms were tested under direct shear to obtain material properties such as shear strength and shear toughness. FRC test results indicated an almost linear increase in the shear strength of concrete with an increase in the fiber volume fraction. Fiber reinforcement enhanced the shear load capacity and shear deformation capacity of RC beams, but 1% fiber volume fraction was seen as optimal; no benefits were noted when the fiber volume fraction was increased beyond 1%. Finally, an equation is proposed to predict the shear capacity of RC beams.Key words: shear strength, fiber-reinforced concrete, RC beam, stirrups, energy absorption capacity, steel fiber, synthetic fiber.

Experimental study of the shear properties of reinforced ultra-high toughness cementitious composite beams

“…Swamy and Bahia (1979) and Liu (2010) showed that for SFRC beams with a reinforcement ratio of 2%-4%, a 0.75%-0.8% volume fraction of steel fiber combined with a small quantity of web reinforcement can result in a ductile yielding behavior. A synergy between fiber and stirrups was shown in (Majdzadeh et al, 2006;Liu, 2010). The maximum load showed 7% synergy for one beam with a 0.14% web reinforcement ratio and a 0.5% volume fraction of steel fiber, and 10% synergy for another beam with the same stirrup ratio and fraction of synthetic fiber (Majdzadeh et al, 2006).…”

“…A synergy between fiber and stirrups was shown in (Majdzadeh et al, 2006;Liu, 2010). The maximum load showed 7% synergy for one beam with a 0.14% web reinforcement ratio and a 0.5% volume fraction of steel fiber, and 10% synergy for another beam with the same stirrup ratio and fraction of synthetic fiber (Majdzadeh et al, 2006).…”

“…This experimental result fully demonstrates the outstanding shear resistance of UHTCC, the use of which can save at least 0.37% on web reinforcement. Majdzadeh et al (2006) indicated that the composite use of stirrups and FRC in slender beams resulted in a synergic influence on shear resistance. However, with respect to the RUHTCC slender beams in the present tests, the ultimate shear strength of beams with stirrups was almost comparable to that of beams without stirrups.…”

Influence of Chopped Basalt Fibers on the Shear Strength of RC Beams without Stirrups

“…It has been well established that the addition of fibers can augment the mechanical behavior of plain concrete such as flexural strength, deformation capacity, impact resistance, compressive and tensile strength, load capacity after cracking, fatigue and abrasion strength, toughness and shrinkage [1][2][3][4][5][6][7][8][9][10][11].…”

Shear Crack Formation and Propagation in Fiber Reinforced Cementitious Composites (FRCC)

“…There are numerous models available to predict the shear capacity of FRCC [1][2][3]. However, understanding of the controlling, fundamental mechanisms is lacking, resulting in limited applicability of particular models.…”