Experimental investigation of GFRP-reinforced and GFRP-encased square concrete specimens under axial and eccentric load, and four-point bending test

This paper presents the results of an experimental study on the axial and flexural behavior of square concrete members reinforced with glass fiber-reinforced polymer (GFRP) bars and embedded with pultruded GFRP structural sections under different loading conditions. The main parameters investigated in this study were the influence of the type of internal reinforcement (steel bars, GFRP bars and pultruded GFRP structural I-sections and C-sections) and magnitude of load eccentricity on the flexural and compressive behavior of square concrete members. To fulfil the objectives of this study, 16 reinforced concrete specimens were tested, of which 12 were tested as columns under compression loading and 4 were tested as beams under flexural loading. The concrete specimens were square in cross section with a side dimension of 210 mm and a height of 800 mm. The experimental results have shown that the steel-reinforced specimens have a higher loadcarrying capacity than specimens reinforced with GFRP bars for all loading conditions. In addition, for concentrically loaded specimens, steel-reinforced specimens have a better ductile performance than specimens reinforced with GFRP bars. In terms of eccentric loading, specimens reinforced with GFRP bars experienced similar ductility as compared to the corresponding steel-reinforced specimens. However, the eventual failure mode of specimens reinforced with GFRP bars was sudden and brittle in nature. However, specimens encased with GFRP structural sections have a higher load-carrying capacity but considerably lower ductility than the steel-reinforced and GFRP bar-reinforced specimens.