Shear strengthening of reinforced concrete beams with hybrid composite plates

Abstract

The effectiveness of hybrid composite plates for the shear strengthening of the reinforced concrete beams was assessed by executing an experimental program. Hybrid composite plate is a thin plate of strain hardening cementitious composite reinforced with carbon fiber–reinforced polymer laminates. Due to the excellent bond conditions between strain hardening cementitious composite and carbon fiber–reinforced polymer laminates, these reinforcements provide the necessary tensile strength capacity to the hybrid composite plate. Two hybrid composite plates with different inclination of carbon fiber–reinforced polymer laminates (45° and 90°) were adopted for the shear strengthening of reinforced concrete beams by bonding these hybrid composite plates to the lateral faces of the beams with an epoxy adhesive. The results showed that these hybrid composite plates have assured a significant increase in terms of load carrying capacity, mainly those with inclined laminates. The shear strengthening contribution of the hybrid composite plates was limited by the tensile strength of the concrete of the strengthened beams since their failure mode was governed by the detachment of the hybrid composite plates that included part of the concrete cover. Advanced finite element method-based numerical simulations were performed using a constitutive model, whose predictive performance was demonstrated by simulating the experimental tests carried out. Using this computer program, a parametric study was executed to evaluate the shear strengthening efficiency of the arrangement and percentage of carbon fiber–reinforced polymer laminates in hybrid composite plates, as well as the influence of using mechanical anchors to avoid premature detachment of the hybrid composite plates.