MODELS FOR CONFINED CONCRETE COLUMNS WITH FIBER COMPOSITES

Many studies have been done to find a convenient representation of physical behavior Fiber Reinforced Polymers for strengthening or retrofitted techniques which can enhance stress-strain performance of existing reinforced concrete structures. FRP composites are used for strengthening applications mainly due to the lightweight, high compressive strength, resistance to corrosion, speed and ease of application and formed on site. Conceptually, the s tress strain relation of concrete as a nonhomogenous and nonlinear composite material is not unique that depends on the many variables. In this study some common mathematical models for concrete in the stress-strain relation have been discussed to clarify mechanical behavior of concrete up to ultimate strain. However models of concrete confined by fiber composites corresponding to Stress -Strain relations of TDY2007 and ACI 2002 codes were compared for strengthening concrete sections. Furthermore it is noted that using FRP material increases both strength and ductility of compressive sections.