Prediction of Shear Capacity of Slender Reinforced Concrete Beams with Steel Fiber

• Published in: Journal of Advanced Concrete Technology Vol. 18; no. 4; pp. 179 - 191
• Main Authors: Hemstapat, Narawit, Niwa, Junichiro, Okubo, Kazumasa
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Concrete Institute 17.04.2020; Japan Science and Technology Agency
• Subjects: Compressive strength; Failure modes; Material properties; Reinforced concrete; Reinforcing steels; Residual stress; Shear; Steel fiber reinforced concretes; Steel fibers; Tensile stress
• ISSN: 1346-8014; 1347-3913
• DOI: 10.3151/jact.18.179

The objective of this research is to propose a simple and accurate prediction method for the shear capacity of reinforced concrete beams with steel fiber (RSF beams). Steel fiber reinforced concrete (SFRC) is being widely used nowadays, with the steel fibers added to the concrete to improve the tensile resistance. First, this research aims to investigate the material properties of SFRC in various concrete compressive strengths, shapes of steel fiber and volume fraction of steel fiber. In order to evaluate the shear capacity, several material properties, such as tension softening curves and fracture energy were investigated in the material tests. Second, four-point bending tests of RSF beams were conducted in order to investigate the shear capacity and diagonal crack pattern. Eight RSF beams with various concrete compressive strengths, volume fraction of steel fiber and stirrup ratios were fabricated and tested. The results revealed that the concrete compressive strength and steel fiber significantly affect the shear capacity of RSF beams. Finally, the shear equation for the RSF beams failing in a diagonal tension failure mode has been proposed by focusing on the residual tensile stress perpendicular to the critical diagonal crack at the failure condition.