Experimental study on the behavior of GFRP reinforced concrete columns under eccentric axial load

In the study, experiments were conducted to investigate the behavior of glass fiber reinforced polymer reinforced concrete columns (GFRP-RCCs) under an eccentric axial load. Nine short columns (L/h = 4) were cast: three each with initial eccentricities of 175 mm, 125 mm, and 75 mm. The test results showed that GFRP-RCCs experienced pressure-side concrete crushing failures. However, the glass fiber reinforced polymer (GFRP) bars in the concrete columns mostly remained intact after the concrete was crushed. Their force-deformation curves did not correspond to the yielding behavior of steel reinforced concrete columns (SRCC) before the ultimate load was reached, and the load eccentricity had a significant influence on the force-deformation curves with increased eccentricity leading to a better ductility performance. Additionally, the force-strain curves of the GFRP bars on the tensile side decreased when the GFRP-RCCs were subjected to eccentric loads, and the extent of the decrease was less than that on the compression side. The study also showed that the bond behavior between the GFRP bars and concrete improved when the GFRP bars were used as longitudinal compressive bars.