Shear behavior of prestressed precast beams made of self-compacting fiber reinforced concrete

• A SCFRC is designed and adapted for its daily use in a precast industry.
• Nine precast prestressed beams were tested in shear.
• Deflections, crack widths and shear strengths were analyzed.
• Steel fibers control cracks propagation. Fibers and stirrups have a synergic effect.
• Although Codes are safe, more analysis on the influencing parameters is needed.

Even after many years of in-depth research the shear behavior of concrete structures is still a subject for debate. Current Design Codes need to be adapted to new materials and production methods. This paper discusses some still unresolved doubts, based on an experimental program consisting of nine prestressed I-beams of different flange dimensions. Shear evaluation is analyzed in accordance with the Codes under different conditions: a combination of fibers with stirrups, the possible influence of flange width on shear strength and the interaction of fibers with other important parameters such as flange width and longitudinal reinforcement. The results obtained show that fibers act as additional reinforcement to stirrups and also that the Codes are within the safety limits as regards shear ultimate limit state (ULS).