Comportamento di un inserto per la realizzazione di un nodo prefabbricato di una struttura a telaio in zona sismica

In Italy, the precast concrete structures are traditionally designed as moment resisting frames with the plastic hinges occurring at the columns bases and with the beams simply supported by the columns. A ductile moment resisting connection between the column and the beam can provide the architectural advantage to design continuous beams with a reduction of the beam depth or an increasing of the span or of the carried load with the respect to the simply supported precast beam. Furthermore the seismic resisting frame can develop the formation of the plastic hinges at the beam-column interface besides at the column base. This paper aims at presenting a finite element analysis (FEA) of a particular beam-column “dry” connection for precast concrete elements. The joint is characterized by the use of high resistance steel bars and of fibre reinforced gout pad in the “Z” shaped beam-column interface to increase the shear resistance of the connection. The non linear analyses are conducted with FE program ABACUS. A plane model has been carried out with plane stress elements. The numerical results show a good performance of the joint, in term of resistance, ductility and energy dissipation. Further experimental studies carried out in the University of Brescia could characterize the real constitutive moment-rotation law for cyclic loading history with increasing amplitude till the failure of the connection. These curves will be used to validate the laws given by the numerical analyses and to study the seismic behaviour of precast concrete structures.