An innovative reinforcement method: the combination of CFRP bars and UHPC layer is applied to the flexural reinforcement of RC beams

Abstract

PurposeEmbedding carbon fiber reinforced plastics (CFRP) bars in the tension zone of reinforced concrete (RC) beams is a widely used reinforcement method, which has the advantages of strong anti-peel ability and high utilization of tensile materials. To further improve the flexural bearing capacity of RC beams, a new composite reinforcement method using the UHPC layer in the compressive zone of RC beams is proposed based on embedding CFRP bars in the tension zone of RC beams.Design/methodology/approachThe finite element model of an RC experimental beam with CFRP bars embedded in the tension zone was carried out by ABAQUS. Besides, the reliability of the finite element model results was verified by comparing with the experimental results. On this basis, the flexural reinforcement effect of CFRP bars and UHPC layers on RC beams was analyzed.FindingsCalculation results show the flexural bearing capacity of the beam strengthened by the new method is 15.9%, which is higher than that of the unreinforced beam, and 10.4% higher than that of the beam strengthened only with CFRP bars. The beam ductility ratio of the new method is 8.25%, which is slightly higher than that of the unreinforced beam and equal to that of the beam reinforced only with CFRP bars embedded in the tension zone. The effectiveness of the new method is further verified by using the analytical calculation method.Originality/valueA new flexural reinforcement method for reinforced concrete beams is proposed, and the effectiveness of the method was verified by experiments and finite element model. The flexural bearing capacity and ductility of the new method were analyzed based on the load-deflection curve. Finally, the possibility of the new method was verified by analytical analysis.

Flexural Reinforcement of Over-Reinforced Beam by Ultrahigh Performance Concrete Layer

“…Te "Tie" method is used to simulate the interaction between beam and pad, and the "Embedment" method is used to simulate the interaction between beam, rebar, and bolt. Te mesh size of the fnite element model is 40 × 40 mm [30,31]. Te fnite element model is shown in Figure 3.…”

“…Te fnite element model of the RC beam was established, and the fnite element model results were compared with the experimental results in the literature [29]. Te rationality of the fnite element model was verifed by comparison of the loaddefection curve, crack distribution, and failure modes, which is a common research method [30,31]. A more detailed study was carried out on the parameters of the new reinforcement method later, including the thickness of the UHPC layer, the cross-section area of longitudinal tension rebar, and concrete strength.…”