Rectangular filament-wound glass fiber reinforced polymer tubes filled with concrete under flexural and axial loading: Experimental investigation

This paper presents results of an experimental investigation on three beams and five short columns, consisting of glass fiber reinforced polymer concrete-filled rectangular filament-wound tubes (CFRFTs). The tubes included fibers oriented at +/-45degrees and 90degrees with respect to the longitudinal axis. Additional longitudinal fibers [0degrees] were provided in flanges for flexural rigidity Beams included totally filled tubes and a tube partially filled with concrete, which had a central hole for reducing deadweight. The effect of reinforcement ratio was examined by using tubes of two different sizes. Flexural behavior of CFRFT was compared to concrete-filled rectangular steel tubes (CFRSTs) of similar reinforcement ratios. Short columns were tested under eccentricity ratios (e/h) of 0, 0.09, 0.18, and 0.24, where h is the section depth. Transverse strains were measured around the perimeter of concentrically loaded column to evaluate confinement effect. The study showed that CFRFT is a feasible system that could offer similar flexural strength to CFRST. The tube laminate structure and its progressive failure contribute to the slightly nonlinear behavior of beams. The CFRFT beam with inner hole had an overall strength-weight ratio, 77% higher than the totally filled beam, but failed in compression. Bulging of CFRFT columns has limited their confinement effectiveness.