A New Model to Assess the Flexural Strength of Steel-Fiber Reinforced Concrete Sections

Structural engineering requires approaches allowing engineers to do simple but reliable calculations. For this purpose, we present an analytical model to evaluate the flexural strength of steel-fiber reinforced concrete sections. The model studies the compressive and tensile sectional behaviors jointly. The tensile zone of the structural element is defined through a linear stress-crack opening softening law, and it is assumed to have a planar crack (the crack surfaces remain plane during the fracture process) as a compatibility equation. The new compressive stress-strain law included in Annex L of the new Eurocode 2 for steel-fiber reinforced concrete analysis describes the compressed zone together with the Bernoulli-Navier hypothesis. A brittleness number is defined, like Hillerborg’s brittleness number for plain concrete, which depends on the size and tensile softening characteristics. The results reveal that this brittleness number influences the flexural strength of steel-fiber reinforced concrete sections. Besides, the model reproduces the size effect and its asymptotic behavior, showing the actual response in flexion of the material. Thereby, the model may be helpful to engineers in designing structural sections of steel-fiber reinforced concrete simply and reliably.