Telai prefabbricati ad assetto variabile

The possibility of realizing dry precast emulative moment-resisting frames is a relevant innovation, while the heritage of precast structures consists mostly in frames with hinged beams and cantilever columns restrained at their base. The transformation of hinges in restraints becomes necessary while facing the need to reduce deformations under severe horizontal loads, especially seismic. Reduced stresses and increased ductility can be achieved, avoiding the ???soft floor??? mechanism through the energy dissipation provided by the steel placed in horizontal members. Precast structures with adaptable restraints (PRESAR) are therefore presented in their essential features, among them the possibility of mix of a dry precast construction technology and the stiffness and redundancy provided by a traditional cast-in-situ frame. A design comparison between 3 precast frames with the same geometries but different static schemes shows how this structural flexibility can be exploited to optimize the structure.