Criteri di progetto e casi applicativi di miglioramento sismico di edifici con struttura a telaio mediante controventi dissipativi includenti smorzatori fluido-viscosi.

This dissertation was aimed at revisiting and integrating energy-based design criteria of dissipative bracing systems incorporating fluid-viscous spring-dampers as protective devices, for the seismic retrofit of frame structures. This objective was pursued by means of two main contributions. The first one concerned the introduction of an additional pre-sizing criterion of these systems aimed at guaranteeing a prompt activation of the spring-dampers starting from the early stages of the seismic response of the buildings where they are installed. The second one consisted in the evaluation of the influence of masonry infills and partitions in the assessment analysis in current state of the examined buildings, as well as in their verification analysis in retrofitted conditions, in order to evaluate the pre and post-intervention seismic performance of these non-structural elements, and the correlation with the response of the frame skeleton members. For this second objective, a no-tension strut model with multilinear “pivot”-type hysteretic behaviour was adopted as substitute element for the infill and partition panels. A trilinear axial force-displacement backbone curve was generated for the equivalent struts, and transformed in the lateral force-drift curve of the panels. The latter was then scanned in terms of sequential performance limits and ranges, so as to accurately follow the damage evolution in the panels. By collecting the results of the activity carried out during the Doctorate, this dissertation was written by presenting and discussing criteria and models, after short introductory notes, directly with the application to a series of demonstrative case studies concerning real buildings with different characteristics. This allowed substantiating the conceptual aspects of the examined topics with their practical implementation and possible use for other scholars and professional engineers operating in the same fields of interest.