Models Reviewed for Predicting CFRP Shear Contribution of Strengthened Reinforced Concrete Box Beam: Fid-Bau Portal

Models Reviewed for Predicting CFRP Shear Contribution of Strengthened Reinforced Concrete Box Beam

Ma, Shengqiang / Muhamad Bunnori, N. / Choong, Kok Keong / Zhao, Rui

Abstract Eight various models for calculating the FRP (fiber-reinforced polymer) contribution to shear from different codes and studies were reviewed and discussed. From all the models, it is found that the effective strain is the most important parameter which lies in all equations except JSCE model. Besides, the six models from guidelines and two from latest literature with different parameters were discussed and applied for calculating shear contribution of 181 FRP shear strengthening specimens collected from existing literature. It reveals that all ratios of calculation related to experimental results showed distributions around the bisector in all equations of models. From the values of total members, the predictions of FRP shear contribution of the beam with a T-section or rectangular section using two models (fib Bulletin 14 and Sayed et al.) were very close to the experimental values and also stood safe sides. Furthermore, one control and four strengthened reinforced concrete (RC) box beam by carbon fiber-reinforced polymer (CFRP) were tested for shear strength. Compared with the experimental results, all theoretical values predicted by the reviewed models overestimated the FRP shear contribution of strengthened members, because the effective strain was overestimated. A coefficient of 1.31, therefore, was also proposed, which divided the formula of the effective strain in the fib Bulletin 14 model according to the experimental effective strain in fiber. The model with the modified effective strain presented a rational prediction in CFRP shear contribution of strengthened RC box beams.