An improvement to Eurocode 2 and fib Model Code 2010 methods for calculating crack width in RC structures: mathematical model and simplified method

A mathematical model for the analysis of the mechanical behaviour of a reinforced concrete tie subjected to a monotonic loading, that considers the effect of the so-called Goto cracks (secondary cracks), is described here. It is shown that the average bond stress along the transmission length depends not only on the concrete strength as assumed by the fib Model Code 2010, but also on reinforcement ratio and bar diameter. The secondary cracks influence also the tension-stiffening effect, reducing it. On the basis of the main results obtained with the general model, an improvement to Eurocode 2 and fib Model Code 2010 methods for calculating crack width in RC structures is proposed. Finally, the theoretical results of crack spacing and crack width are compared with experimental data obtained from extensive research on RC ties.