Adeguamento sismico di edifici esistenti in calcestruzzo armato tramite esoscheletri dissipativi

The gap between safety requirements of modern building codes and seismic performance of existing structures requires the design of retrofit interventions for improving the structural safety of buildings. Among the various retrofit techniques, exoskeletons are gaining increasing interest within the scientific and professional community since they allow for modification of the building's seismic response, increasing strength, stiffness, and ductility of the existing structure, without interrupting its operability, as the intervention is carried out entirely from the outside. At present, the Italian Building Code does not provide specific guidelines for designing this structural typology. Therefore, the primary objective of this thesis is to evaluate and validate a design procedure for the implementation of dissipative exoskeletons. The proposed methodology has been validated through its application to a case study building, consisting of an existing reinforced concrete residential building located in L'Aquila. The effectiveness of the retrofit has been evaluated through nonlinear static and dynamic analyses, performed using the SeismoStruct software. The results highlighted the high seismic vulnerability and severe non-compliance of the as-built structure with respect to current standard requirements. Following the retrofit intervention, full code compliance was achieved, satisfying safety verifications for both the Life Safety (SLV) and Damage Limitation (SLD) Limit States. Furthermore, damage concentration was observed within the BRAD dissipative devices, which are specifically designed to be easily replaceable, along with significant reduction in the elongation of the fundamental period, confirming the effective mitigation of structural damage. The design procedure was applied to two different exoskeleton configurations (parallel and orthogonal). The results were positive and comparable for both schemes, demonstrating the reliability of the proposed method and its suitability for practical professional application.