Shear Behaviour of V-shape Webbed Steel Fibre Reinforced Concrete Beams

Asymmetrical three-point bending tests were performed on beams with four different types of V-shaped/tapered webs (V-beams) containing various percentages of steel fibres by volume (0, 0.6 and 1%) as well as longitudinal reinforcement in the form of two 16 mm diameter steel bars. The test results revealed that the ultimate shear capacity increases significantly with increasing fibre content and larger web cross-sectional areas. The normalised shear stresses at ultimate resistance are relatively constant for the various types of V-beams indicating that shear capacity is highly dependent on the entire cross-sectional area of the web. An average increase in shear strength of 49% for beams containing 0.6% fibres and 74% for beams containing 1% steel fibres was observed for V-beams when compared to their reference beams containing no fibres. Furthermore, the results show that the widely used assumption where shear is resisted entirely by an effective rectangular cross-sectional area calculated as the product of the narrowest part of the beam (bbww) and the effective depth (dd) can result in over-conservative shear predictions for V-beams.