Nonlinear seismic analysis of gravity designed RC structures

This paper illustrates numerical simulations and comparisons with experimental results of existing RC beam-column sub-assemblages reinforced with smooth bars. The specimens reproduce parts of concrete structures designed only for vertical loads without any reinforcing detail rule (such as inadequate bars lap splice, absence of hoops within the joint panel) built in Italy during ‘50s-‘70s. In particular, in this paper is paid attention to the nonlinear models developed for predicting the failure mechanism experimentally observed, taking also into account the bond-slip phenomenon among the longitudinal bars and surrounding concrete. The proposed models are not time-consuming and may be easily implemented in any general-purpose finite element program for numerical simulations of concrete structures. These models represent an useful tool for seismic assessment with a good accuracy of non-ductile RC existing structures.