Numerical study on fracture behavior of CFRP-strengthened self-compacting concrete beams

This research is dedicated to the numerical investigation of the fracture behavior of notched self-consolidating concrete (SCC) beams which are strengthened by carbon-fiber-reinforced polymer sheets (CFRP). The beams have been constructed with an initial notch in the middle of span and reinforced with a CFRP sheet under the beam. Therefore, the load-carrying capacity of the specimens, shear stresses in CFRP, and crack mouth opening (CMOD) have been documented. Furthermore, specimens have been modeled using the finite-element approach and the nonlinear static analysis. The validity of the numerical modeling has been established through comparing the experimental results with those of numerical simulations. The effect of variation in different parameters such as sheet thickness, concrete mechanical properties, beam height and adhesive strength have been investigated via numerical analyses. The results show that in experimental and numerical models, the load-crack mouth opening (P-CMOD) curves have two peak load points. As the load increases, the first peak value is obtained, which is then followed by a descent in the load-carrying capacity. By further implementing the load, the second peak value is reached on account of the relatively high cohesive impact of the CFRP sheet. Moreover, it is observed that in P-CMOD curves the first and second peak points increase as the concrete strength and the beam height increase, though the rate of this growth is less for $P_{2max}$ . While the adhesive strength and thickness of the CFRP sheet have the most influence on the second peak load which indicates the performance of the CFRP sheet.