Experimental Investigation on Concrete Confined by Fiber Reinforced Polymer and Comparison with Theoretical Model

Prevalently compressed concrete columns can be transversely confined in order to obtain increase in strength and ductility. Generally, two principal methodologies of advanced confinement are used: the "Wrapping" technique which consists of wrapped concrete columns using thin carbon or glass flexible straps epoxy-bonded concrete surface; and concrete filled FRP tubes (CFFT) in which the tube is the pour form, protective jacket, confining mechanism, and shear and flexural reinforcement. The proposed model consists of a generalization of the theory of elasticity, i.e. a step by step application of Navier classical relations which define the stress strain laws in states of triaxial stress. The theoretical results are compared with experimental compression tests carried out on ten cylindrical concrete specimens confined with two different typologies of fiber composite tubes.