Title: Minimum Reinforcement Ratio for Fiber-Reinforced Polymer Reinforced Concrete Rectangular Columns

Author(s): Ching Chiaw Choo, Issam E. Harik, and Hans Gesund

Publication: Structural Journal

Volume: 103

Issue: 3

Appears on pages(s): 460-466

Keywords: columns; failure; fibers; polymers; reinforcement ratio

DOI: 10.14359/15325

Date: 5/1/2006

Abstract:
Strength interaction (P-M) analyses of rectangular concrete columns reinforced with fiber-reinforced polymer (FRP) bars identified two failure mechanisms: premature-compression failure and brittle- tension failure. The study concluded that brittle-tension failure was more likely to occur due to the low ultimate tensile strain of FRP bars. In this paper, an analytical approach is presented to identify both failures and to avert brittle-tension failure of such columns to a failure controlled by concrete crushing. This is achieved by providing a reinforcement ratio r f that is greater than a minimum required reinforcement ratio r f,min. Interaction diagrams in the form of tensile elastic modulus-tensile strain (Eft-eft ) have been developed to facilitate the determination of rf,min. The proposed approach permits the evaluation of rectangular concrete columns reinforced with FRP bars to be carried out in a manner similar to steel- reinforced concrete columns.