Experimental study on fracture behavior of notched self- consolidating concrete beam strengthened with off-axis CFRP sheet

摘要

In this study, the effects of fiber orientation within the carbon fiber reinforced (CFRP) sheets, on the fracture mode and crack growth of specimens were investigated by constructing five groups of initially notched self-consolidating concrete beams, and strengthening them with CFRP sheets in the tensile area. Furthermore, the bearing capacity, strain variation along the sheet, crack mouth opening, and the midspan displacement were recorded by varying the height of the beams and the initial notch lengths. The results indicate that the load-crack mouth opening curves have two peak load points. First, the applied load increases up to one peak value and then there is a drop in the load-caring capacity. Afterwards, the applied load is improved to another peak value due to the relatively high cohesive effect of the CFRP sheet. The results show that as the height of the beam section increases, or the initial notch length decreases, the first and the second peak loads increase. By comparing the specimens with different fiber angles in each group, it was observed that the specimen with fiber angle 0 degrees has a higher capacity relative to other angles, yet its failure occurs in a lower displacement. Furthermore, with the help of finite element software and nonlinear static analysis, the behavior of the aforementioned beams including the stress and strain distributions in the CFRP sheet, and the sheet-to-concrete bond zone have been examined and compared with the existing experimental results for validation.