Legame isteretico di aderenza per barre di armatura lisce

In recent years there has been wide use of non-linear dynamic analysis for the evaluation of existing structures in areas of high seismic risk. The monotonic and cyclic non-linear analysis models for reinforced concrete (RC) structures have to properly account for interaction mechanisms between reinforcing bars and surrounding concrete. In fact, numerous numerical models, which can explicitly account for the slip between rebars and concrete through the definition of the local hysteretic bond-slip relationship, has developed in recent decades. The existing literature regarding the bond performances of deformed reinforcing bars offers many experimental data and constitutive relationships, monotonic and hysteretic, taking into account the main parameters that influence bond capacities. With respect to plain bars, commonly used in reinforced concrete buildings before the 1970’s, there are almost no references to hysteretic bond mechanisms. In this paper, basing on experimental results from monotonic and cyclic pull-out tests, a bond-slip hysteretic constitutive model for plain reinforcing bars is presented and discussed.