Reliability Study of Concrete Columns Internally Reinforced with Non-Metallic Reinforcements

This study focuses on the behaviour of full scale size concrete columns reinforced internally with non-metallic reinforcements i.e Glass Fibre Reinforced Polymer (GFRP) reinforcements combined bending and axial loads. The experimental investigation consists of Series A and B. Each series has twenty four column specimens with different parameters like shape of columns, reinforcement ratios, types of GFRP reinforcements, slenderness of the columns and grades of concrete. Based on this study, the strength expressions are derived using the equilibrium, strain compatibility, and stress-strain relationship for the constituent materials. For a known eccentricity, the expressions for axial thrust-moment interaction relations are developed for slender columns and the effect of secondary moments incorporated in the analytical study. Also Finite element modelling and analysis of GFRP reinforced concrete columns are performed to simulate the behaviour of the columns under various parametric conditions. A probabilistic framework is necessitated because of the presence of a large number of uncertainties pertaining to the theoretical models and the inherent randomness in the various design parameters. The full range of possible values of load eccentricity, from axial load to pure bending is investigated in the study. Finally, based on the reliability index, appropriate resistance factors are arrived at using the concepts of reliability based design.