Numerical Modeling of Reinforced Concrete Columns Strengthened with Composite Materials

The use of Near-surface Mounted (NSM) FRP bars is an efficient strengthening technique to enhance the flexural strength of RC structures. This article is intended to analytically investigate the effectiveness of Glass Fiber Reinforced Polymer (GFRP) bars in combination with GFRP wraps on the flexural capacity of reinforced concrete (RC) columns with Fiber Element Modeling approach. The accuracy and reliability of the proposed fiber-based modeling method is demonstrated by numerical models on seven half-scale experimental RC reference columns under axial and cyclic lateral loads. These reference specimens are comprised of seven half-scale RC columns including two unstrengthened and five strengthened specimens with two GFRP bar reinforcement ratios under three axial load levels. Additionally, eight RC strengthened columns are analytically simulated with four complementary GFRP bar reinforcement ratios under two axial load levels. As the numerical results represent good correlation between the fiber-based modeling approach and the experimental results of the reference RC columns, it is concluded that the numerical simulations explicitly predict a considerable improvement in the flexural strength of the RC columns retrofitted with Glass Fiber Reinforced Polymer bars.