7 Conclusions
The study of the mechanical performance of RC/FRC frames is one of the topics at the forefront of today’s research activities in the structural domain, which is mainly devoted to experimental behaviour of columns, beam–column joints and frames subjected to cyclic actions. Beyond any doubt, the performance of FRC members, even devoid of transverse reinforcement, positively affects tensile, shear and bending behaviours.
The purpose of this work is to investigate the use of fibre-reinforced materials in the critical regions of concrete frames subjected to seismic loads, where a high dissipation ability is required. A numerical investigation focused on the global behaviour of earthquake-resistant RC plane frames with FRC materials in the joint regions was presented and discussed. Static and dynamic non-linear analyses were performed, based on a diffused plasticity model with fibre sections. Investigations on a number of variables such as frame geometry, FRC/RC material grade combinations, lateral load profile, joint modelling technique and floor in-plane constraint are carried out. Frames with FRC in joints prove to have better performances than reference RC frames. In fact, in FRC frames the total base shear capacity is higher than in reference frames, while the behaviour factor is not affected as much and the collapse probability is increased. Therefore, for a given geometry, adopting fibre-reinforced materials in the joints brings in not only a higher lateral stiffness, but also a higher global capacity, leading to reduced lateral displacements in case of nondestructive earthquakes (Serviceability Limit State).
