Flexural Performance of Concrete Beams Reinforced with Hybrid FRP-Steel Bars: A mini review

Abstract

Reinforced concrete beams are the most generally used structural parts in building, bridges, and many other structures. In the past two decades, many investigations have been conducted using various fiber-reinforced polymer (FRP) material types /steel bars to reinforce concrete beams under flexural test. The purpose of this paper is to review the flexural performance of concrete beams reinforced with hybrid FRP and steel bars to better understand their behavior. The main parameters addressed by researchers were dimensions of beams, FRP bar material type, and hybrid reinforcement ratio. The researchers established that the use of the combination between steel and FRP reinforcement bars improves the performance of the concrete beams. Moreover, the studies showed that the ductility of the hybrid reinforced beams increased compared to that of conventional steel reinforced beams, however, it decreased when the ratio of (Af/As) increased. The application of using hybrid FRP/steel bars in reinforcing concrete beams will further increase upon utilizing techniques for reducing the brittleness and higher cost of FRP bars. The general structure of this paper consists of presenting the formulas offered by ACI 440.1R-15 building code relating to the flexural strength calculation of concrete beams reinforced with FRP/steel bars. The paper also details some of the current experimental tests and analytical works published for concrete beams reinforced with hybrid system, and outlines research directions and identifies gaps required for additional research.