Analytical and numerical analysis of the behaviour of RC beams flexural strengthened with CFRP

Abstract

Experimental research regarding the flexural strengthening of reinforced concrete (RC) structures with Carbon Fibre Reinforced (CFRP) systems using the Externally Bonded Reinforcing (EBR) and the Near Surface Mounted (NSM) techniques has been carried out at the University of Minho. Considering the experimental results of this research, the performance of the ACI and fib formulations for the EBR flexural strengthening was appraised in this paper. The same was done in terms of NSM technique adopting for the CFRP debonding strain a value that is 70% of the CFRP ultimate strain, according to the recommendations of the ACI Committee 440. However, the experimental results show that the CFRP debonding strain is dependent on the CFRP percentage and existing longitudinal steel reinforcement ratio. To estimate an equation for the prediction of the CFRP debonding strain, which takes into account these parameters, a numerical model was applied to the simulation of the tests carried out.