Moment redistribution in Hybrid-RC continuous beams with T-section using FEM

Abstract

The use of Fiber Reinforced Polymers (FRP) alone or together with steel as a reinforcement material in reinforced concrete, especially in structures exposed to bad weather conditions, has recently received much attention. This research was conducted with the aim of investigating the effect of different parameters on the amount of moment redistribution in continuous T-shaped concrete beams reinforced with combinations of steel reinforcement and Glass-FRP (GFRP). For this purpose, ABAQUS finite element software was used. The research variables were the ratio of GFRP reinforcement to steel in the positive and negative moment areas, the type of materials in these areas, and the effect of stirrups on the moment redistribution. After verification of modeling, new models were built, and variables were investigated. The results show that it is better for the ratio of Af/As in the upper and lower parts of the beam to be more than one and less than 0.75, respectively. Therefore, theoretically, the best case of moment redistribution is when the negative and positive reinforcement is GFRP and steel, respectively. Similar to the Steel-RC codes, an equation based on the maximum strain in the farthest tensile bar is introduced to calculate and limit the maximum moment redistribution in these beams.