Crack Width Prediction for Concrete Beams Strengthened with Carbon FRP Composites

Strengthening of RC beams and slabs using fiber-reinforced polymers (FRPs) is known to control crack width. However, no specific provisions are provided by most international design codes for predicting crack width in FRP-strengthened members. In this paper, models for predicting crack width of conventional RC members in five international codes are extended to FRP-strengthened beams by introducing appropriate modifications to account for the effect of FRP composites. Predictions of the crack width by the resulting models are evaluated and compared with experimental results. Both analytical and experimental results showed significant reductions in crack widths due to FRP strengthening. The efficiency of controlling crack width, however, decreased with increased amount of steel reinforcement and increased with increasing the ratio of FRP plate to beam width. Comparison of the codes* predictions of the maximum crack width against experimental results revealed that some predictions are in good agreement with the measured values while others overestimate the maximum crack width by a significant margin. (c) 2017 American Society of Civil Engineers.