Axial load-bending moment diagrams of GFRP reinforced columns and GFRP encased square columns

Fiber reinforced polymer (FRP) pultruded materials are available in a wide variety of shapes, including bars, I-sections, C-sections and other structural sections. Due to their high durability, low self-weight and reduced maintenance costs, these FRP materials are becoming a competitive option for replacing steel as structural materials especially in corrosive environments. This paper summarizes an experimental program on the axial and flexural behaviour of square concrete members reinforced with glass fiber reinforced polymer (GFRP) bars and embedded with pultruded GFRP structural sections under different loading conditions. Furthermore, an analytical model is presented to predict the axial load-bending moment interaction diagrams of the experimentally tested specimens. It can be concluded from this study that the analytical models provide reliable estimates of the maximum load and bending moment capacities of GFRP reinforced and GFRP encased concrete columns. In addition, a parametric study was conducted to study the effects of concrete compressive strength and longitudinal GFRP reinforcement ratio on the structural performance of GFRP reinforced square concrete columns.