Flexural response of FRC corbels

A strut-and-tie macro-model is proposed to determine the flexural response of fiber reinforced concrete (FRC) corbels, reinforced with longitudinal bars and subjected to vertical load. The effects of the corbel geometry, the percentage of steel fibers, and grades of concrete and steel bars are also included. The model, which is specific for FRC corbels with hooked steel fibers, allows the determination of load levels, and corresponding displacements, associated with the first cracking, yielding of the main steel bars and crushing of the concrete strut. The sequential occurrence of these phenomena is established, depending on the amounts of steel fibers and reinforcing steel. The simplified flexural response of corbels, in terms of load–deflection curves, is in good agreements with experimental data collected from the literature. In addition, prevision of bearing capacity and failure modes (yielding of main steel or crushing of concrete strut) is obtained with reference to other experimental data collected from the literature. Finally, some recommendations on the design of FRC corbels are given.