Flexural and Shear Resistance of Steel Fiber–Reinforced Lightweight Concrete Beams

In the present paper an analytical model is proposed that is able to determine the shear resistance of lightweight reinforced concrete beams with longitudinal bars, in the presence of reinforcing steel fibers. The model is based on the evaluation of the resistance contribution resulting from beam and arch actions. For the resistance contribution of main bars in tension, the residual bond adherence of steel bars and the crack spacing of reinforced concrete (RC) beams in the presence of fibers are considered. The contribution in terms of postcracking resistance in the tension zone of the beams is also included. The model was verified on the basis of experimental data available in the literature and is able to include the following variables in the resistance provision: diameter and number of steel bars, depth to shear span ratio, resistance of materials and fiber characteristics, crack spacing, tensile stress in main bars, residual bond resistance, postcracking tensile resistance, and size effects. Finally, some of the more recent analytical expressions able to predict the shear resistance of fibrous concrete beams are mentioned and a comparison is made with experimental data.