Verification of an energy-based design procedure for seismic retrofit of a school building

A viable design criterion of supplemental damping strategies for seismic retrofit of frame structures, recently proposed by the first author (Terenzi, 2018), is applied in this paper to a school building in Florence dating back to the early 1980s. The building is composed of two portions, with reinforced concrete and steel frame structure, respectively. Similarly to several other buildings of the same period, the structure is infilled by heavy reinforced concrete panels interacting with the frame elements under horizontal loads. A careful reconstruction of the structural characteristics of the constituting members, based on the original design documentation and on-site testing campaigns, highlighted specific drawbacks in current state, related to a remarkable degration of the materials and a poor performance of several elements. The retrofit solution considered in this study consists in removing the infill panels and replacing them with a set of dissipative braces incorporating fluid viscous dampers as protective devices. The design is carried out by the sizing criterion mentioned above, targeting an elastic structural response up to the maximum considered earthquake normative level.