Issue 46

H. Zhu et alii, Frattura ed Integrità Strutturale, 46 (2018) 361-370; DOI: 10.3221/IGF-ESIS.46.33 365 plate increased, the stress on the rebars stopped increasing, bond slip happened to the rebars and concrete, the CFRP plate shouldered the main tension. At that moment, the ultimate carrying capacity and failure mode of the strengthening beam mainly depended on whether the binding between the CFRP plate and concrete was tight. The main failure modes included crushing of concrete beam, fracture of CFRP plate, debonding of CFRP plate and binding materials, debonding of the protective layer of concrete and debonding of concrete and binding materials. Comparison between simulated values and test values To verify the accuracy of the finite element model, the analysis results of L1, L2 and L3 beams were firstly selected. The specific parameters of the beams are shown in Tab. 2. No. of test specimen L1 L2 L3 Width of CFRP plate (mm) 10 10 10 Number of CFRP plate (n) 6 4 4 The embedding angle of CFRP plate 90 90 90 Spacing between CFRP plate (mm) 100 150 150 Depth of groove (mm) 20 20 20 Shear span ratio(a/h0) 2.33 2.33 2.71 Table 2 : The parameters of the verified beams. The mid-span vertical displacement of the model beam was extracted as the mid-span deflection of the beam. The 2-fold value of the reactive force at the cushion blocks was taken as the concentrated load of the beam. The load-deflection curve of the strengthening beam was drawn. The test values were compared with the simulated values to verify the accuracy of the model. The comparison results are shown in Fig. 2, 3 and 4. Figure 2 : The load-deflection curve of L1. It could be noted from the load-deflection curves that the differences between the simulated values and test values were small, suggesting the high accuracy of the finite element model. The comparison results of the ultimate load values of the test beams and simulated beams are shown in Tab. 3.