Active Confinement of Structural Members for Seismic Strengthening of R/C Frame Buildings

Active confinement (AC) of structural members is gaining growing attention in the academic and professional communities as advanced seismic retrofit strategy of buildings. The study presented here is focused on the application of a highly performing AC technology, so named CAM (Active Confinement of Masonry), conceived over than twenty years ago in Italy for masonry structures, and subsequently adapted with effective results to reinforced concrete ones (named, for extension, CAM-R/C). A representative case study is particularly examined, i.e. a school built in the early 1960 in Friuli Venezia Giulia region, Italy. A seismic assessment analysis of the building is carried out in its current conditions, also supported by preliminary diagnostic investigations, which highlights several seismic deficiencies, especially in terms of shear response of columns and beams. Thus, a retrofit intervention based on the application of the CAM-R/C system is designed, which allows attaining a substantial improvement of the structural performance. A detailed description of the case study characteristics, the design criteria adopted for the considered seismic strengthening strategy, drawings of the interventions, and a synthesis of the seismic analyses developed in original and retrofitted configurations are offered in the paper