Strength of concrete columns reinforced with Glass fiber reinforced polymer

Due to low compressive strength and low compressive elastic modulus in comparison with these in tension, GFRP reinforcement is often used for bending elements and is rarely used for compressive structures. In this paper, the authors used finite element (FE) method based on Abaqus software to evaluate the axial load-carrying capacity of GFRP reinforced concrete (RC) columns under varying concrete grades, GFRP reinforcement ratios and tie configurations. The model of the specimens is developed using concrete damage plastic (CDP) model and linear elastic material model for GFRP bar. The consistence of the FE method is verified by the experimental results of a series of columns that tested by current authors. The analytical results show that the selected numerical method can accurately predict the behavior as well as the ultimate capacity of the columns. From simulation results, it is clear that the contribution of GFRP to the load-carrying capacity is considerable in columns with low concrete grades. While using higher concrete grades, the contribution of GFRP decrease, at concrete grade B60, contribution of GFRP is almost unimportant (2.74 %). Influence of tie spacing on load-bearing capacity of columns is also investigated. Accordingly, reducing tie spacing leads to increase load-carrying capacity. Based on study results, the authors recommend to limit tie spacing less than eight times of the GFRP bar diameter.