Numerical Analysis of Concrete Elements Reinforced with GFRP Bars under Concentric and Eccentric Loadings and Four-point Bending

Abstract

Glass Fiber Reinforced Polymer (GFRP) bars with significant corrosion resistance lead to an improvement in the performance of concrete structures and a significant reduction in costs. High ratio of tensile strength to weight, non conductive, and non-magnetic properties are other features of GFRP bars. Recent international design standards, such as ACI 440.1R-15 do not recommend including FRP reinforcement in compression, so they replace them by concrete in calculations. The purpose of this study was to investigate the effect of concentric and excentric axial loading on the axial capacity and ductility of GFRP reinforced concrete columns compared to steel reinforced concrete columns, comparison of flexural capacity of GFRP reinforced concrete beams with steel reinforced concrete beams, and also the effect of compressive bars on the bending capacity and ductility of GFRP reinforced concrete beams. In this study, concrete beams and columns were modeled using finite element software ,ABAQUS. Experimental data from previous studies were used as a criterion for numerical investigations and the model results were validated using the available experimental data. The results demonstrated that the average load carrying capacity of GFRP reinforced concrete columns is about 93.5 percent of steel reinforced concrete columns. GFRP reinforced concrete columns under concentric loading have greater load carrying capacity than GFRP reinforced concrete columns under eccentric loading which is more significant for steel reinforced concrete columns. The average flexural strength of steel reinforced concrete beam was about 90% of GFRP reinforced concrete beam. Also, the ductility of GFRP concrete beam specimens was greater than that for the steel beam specimen. Using GFRP compression reinforcement resulted in higher energy absorption and ultimately higher ductility of the GFRP concrete beams. Also, the results showed that GFRP compression reinforcement does not significantly increase the flexural strength of beams.