Concrete confined by FRP systems: Confinement efficiency and design strength models

This paper presents a large database including results from compression tests performed on over 450 concrete cylinders externally wrapped with Fiber Reinforced Polymer materials. The collected results were first employed to perform a statistical evaluation of the FRP strain efficiency factor; in particular, the influence of the type of fiber and the strength of the unconfined concrete were considered. New relationships for estimating the compression strength of the FRP confined concrete were then developed through best-fit analyses. Finally, a procedure available in the literature was applied by the Authors for the statistical determination of the FRP confined concrete strength to use for design purposes.