Effect of Critical Test Parameters on Behavior of Glass Fiber-Reinforced Polymer-Reinforced Concrete Slender Columns under Eccentric Load

This paper intends to experimentally and theoretically support the North American technical committees engaged in developing design provisions for slender glass fiber-reinforced polymer-reinforced concrete (GFRP-RC) columns. Consequently, 22 full-scale slender GFRP-RC columns with slenderness ratios of 23 and 33 were produced and tested at four different initial eccentricities (0, 16, 33, and 66% of the column diameter). Moreover, the levels of GFRP-longitudinal and transversal reinforcement were also observed and are presented. During all testing phases, the GFRP-reinforcement proved its capacity to maintain stability and resistance to the applied loads. An analytical second-order model accounting for material and geometrical nonlinearities was then developed to extend the parametric study and include additional parameters such as the longitudinal tensile modulus of the GFRP bars. A model for slender GFRP-RC columns was developed by discretizing the section into several integration layers. The ACI stability index corresponding to the ratio of the secondary to the primary moment of 1.4 is applied to GFRP-RC columns to define the permissible tensile design strains at which acceptable lateral deformations are expected. The derived model correlated substantially with the test results. Lastly, based on the experimental results and the developed model, the permissible tensile design strain of the GFRP bars was proposed to be limited to 0.9% to avoid stability failure.