Shear behaviour of new beams made of UHPC concrete and FRP rebar

The primary objective of this study was to develop a new type of high-performance lightweight beam with improved performance over conventional reinforced concrete (RC) by adding fibre-reinforced polymer (FRP) reinforcing rebar to ultra-high-performance concrete with microfibre reinforcement (UHPC-SFR). This new type of beam was designed to be lightweight, to have high compressive and tensile strength, to be able to sustain large bending moments, and to be resistant to shear. The main objective was to verify the mechanical behaviour of the beams and to compare it with the behaviour of typical RC beams. An experimental program was designed to identify its failure modes and bending behaviour. The results indicate that the behaviour of such RC beams is comparable to typical RC beam behaviour to a certain extent. An analytical model for validating this concept is presented here, which is based on the typical material behaviour law hypotheses of nonlinear mechanical beam behaviour. The load-displacement and moment-curvature relationships predicted using this model were compared to the experimental results obtained for several large-scale specimens. The comparisons revealed a good correlation between the analytical and experimental results and illustrate the potential of these composite beams in civil engineering structures.