Size effect of compressed concrete in four point bending RC beams

A mechanical model is proposed to study the behaviour and ductility of reinforced concrete (RC) beams. The aim is to reproduce numerically the experimental results of Weiss et al. (2001), where a size effect on the average strain of compressed concrete has been measured by changing the distance of external loads in four point bending beams. Precisely, the mechanical responses of RC members in bending are evaluated by modelling the progressive crushing of compressed concrete. A good agreement between numerical and experimental results has been obtained for different types of beams. The proposed approach also shows some differences from Eurocode 2, where size effect on the structural response of compressed concrete is not taken into account.