Indagine numerica del comportamento di un sistema di appoggio metallico per pannelli prefabbricati in calcestruzzo

Although several works have been focused on the seismic behaviour of RC frames with masonry infills, the dynamic and non linear behaviour of pre-cast structures under seismic actions, with pre-fabricated RC panels used as curtain walls, is still not well known, due to the lack of studies on the interaction of the RC frame and the external pre-cast concrete panels. In common design practice, the bracing effect of the panels on the seismic response of the building is ignored. However, this assumption might be in some cases unsafe or uneconomical in the design of the RC columns of a seismic resisting frames. One of the problems related to precast RC panels, is that the behaviour of the supporting systems under earthquake actions is not well understood, both with respect to their strength and ductility. This paper aims at presenting finite element analyses (FEA) of a particular steel support system used to connect pre-cast concrete panels to concrete structures. The non linear analyses are conducted with FE program DIANA. A three dimensional model has been carried out with tetrahedral elements. The non linear behaviour of the materials and of the contact surface between the panel and the support system are considered. A rotating smeared crack approach has been used to model the concrete cracking zone around the anchors of the support system. The numerical results show a good performance of the support system, both in term of resistance and ductility, so that under seismic actions the pre-cast panel might be act as stiffening and bracing elements in an RC frame