Studio sperimentale di tecniche per il rinforzo di nodi trave pilastro d’angolo di strutture a telaio in c.a.

The results of full-scale tests on corner beam-column joints subjected to cyclic loads are presented herein, with the aim ofevaluating the effectiveness of different techniques for the seismic retrofitting of corner joint of R.C. frames designed for gravity loads only. The first retrofitting technique involves the jacketing of the joint and the structural elements converging in it with high performance fiber-reinforced concrete. The second solution is characterized by the adoption of a steelinsert coupled with the only restoration of the joint cover concrete or with the jacketing of the structural elementswith HPFRC. The results highlighted the high vulnerability of the unretrofitted corner beam-column joints and the significant role of the slippage phenomena connected to the adoption of smooth reinforcement with hooked end anchorages. From the tests on the specimens retrofitted with the application of a HPFRC jacket to the structural elements it has been evident how this solution allows to improve the strength of the joint, reaching at the same time an adequate level of ductility. The solutions with the steelinsert have been demonstrated effective in providing asufficient protection to the joint panel and allowing the relocation of the collapse mechanism from the joint to the beam. They are susceptible tofurther improvements to obtain more benefits in terms of strength capacity.