Experiments and Finite Element Analysis of GFRP Reinforced Geopolymer Concrete Rectangular Columns Subjected to Concentric and Eccentric Axial Loading

Despite a number of recent studies illustrating the effective use of Glass Fibre Reinforced Polymer (GFRP) rebars as longitudinal reinforcement for concrete compression members. There is a lack of sufficient experimental and numerical studies on their combined action response. This paper demonstrates the use of finite element analysis to predict the response of GFRP reinforced geopolymer and ordinary Portland cement concrete columns under concentric and eccentric axial load in light of experimental data used for validation. The commercial numerical analysis software ABAQUS was used to carry out a parametric study using different material models, element types and mesh sizes. The concrete was simulated using reduced integration 8-noded hexahedral elements, C3D8R. The elasto-plastic material behaviour and the post-peak degradation in strength and stiffness of the concrete were modelled using the widely used concrete damage plasticity model available in ABAQUS. As for the GFRP bars and stirrups, a linear elastic behaviour was considered. To validate the model, the measured load-deflection responses were compared with the predicted curves. It was found that the experimental curves were in close agreement with the predicted load–displacement responses. The predicted N-M strength interaction diagrams matched the measured curves from the experiment, particularly for GFRP RC columns with a large spacing between the ligatures because they exhibited ductile failure which was well captured by the numerical model.