Structural effectiveness of FRP materials in strengthening RC beams

• Structural behavior of concrete beams externally reinforced to flexure and/or shear with FRP systems.
• Increase of strength and control of ductility of strengthened RC beams.
• Performance/deformability and strength factors.
• Holistic design approach, effectiveness of strengthening intervention.

The objective of this paper is to provide an overview of the state of the art concerning the structural behavior of concrete beams externally reinforced with Fiber Reinforced Polymers (FRP) systems. The relevant aspects that mostly characterize the overall performance of strengthened beams, such as strength increase, ductility, and the ability to dissipate the internal strain energy are illustrated by means of a critical analysis of the results obtained from a multiphase an extensive ongoing experimental investigation carried out at the University of Calabria. The latter showed how a stable and controlled progressive failure of reinforced concrete (RC) beams strengthened with FRP materials can be obtained through a holistic approach. The basis of a holistic design is the concept of “performance factor”, obtained by the product of “deformability” and “strength” factors.