Strong-Back System Coupled with Framed Structure to Control the Building Seismic Response

In the present paper, the coupled behavior of structural systems obtained by connecting a moment resisting frame with a vertical elastic truss, known in the literature as strong-back, which acts as a mast by imposing to the a given lateral deformed shape, is investigated. The rigid behavior of the strong-back, which is designed in to remain in the elastic field under strong seismic ground motion, imposes a uniform inter storey drift along the height, thus avoiding undesired effects such as soft storey and weak storey mechanisms. , the whole structural system may be, at first approximation, modelled as an equivalent Single Degree Freedom system thus allowing for an analytical description of its response. In particular, in the work the attention paid to the mutual actions exchanged by the strong-back and the frame by solving the static equilibrium equations, a shear type behavior for the frame. Finally, some numerical simulations of frame systems with strong-back as subjected to earthquake ground motions are developed, encompassing both shear type frames and frames flexible beams.