A New ADAS System for Seismic Retrofitting of Framed Structures by Mean's of the New Hysteretical "I" Device

The seismic retrofitting of the structures can be carried out by strengthening some of the main structural elements so as to give a greater resistance to the earthquake thanks to the increasing of the structural stiffness as well as its energy dissipation capability. The ADAS systems are characterized by the employment of some non-structural elements with high dissipation capability in order to preserve the main structure. In the paper a hysteretical steel device, created by the same authors is used; it is capable of dissipating the energy transmitted by the seismic event, by means of repeated hysteresis cycles are used. This device was already the object of other publications but in this paper we study a different way of coupling between the frame and the proposed device. Namely, in the previous works the load was transferred from the frame to the device by means of tie rods acting only under traction. In this case the tie rods have been replaced by a rigid braces acting both in traction and compression. The system of load transferring was changed too, as well as the coupling frame-device which now is capable of deleting the vertical component of the load, transferred from the device to the mid-span of the frame, thus avoiding any damage along the beam frame.