Retrofitting of existing historical masonry building complex through base seismic isolation: the project of the Palazzo del Governo in Livorno

In the framework of project applications for seismic improvement and retrofitting of existing masonry structures, the ongoing design project of the "Palazzo del Governo" in Livorno applies a retrofit solution through base seismic isolation. The rationalist building, built between the 1930s and 1940s, cointains strategic offices such as the Prefecture and the Police Headquarters of Livorno and the State Archives on the top floor. Considering the monumental constraint, the primary goal is to implement seismic retrofitting through minimally invasive structural work, ensuring that the strategic activities taking place in the building are not interrupted. The proposal to implement basic seismic isolation comes from a comprehensive analysis of the vulnerabilities of the building and its specific characteristics: it is independent on all sides from other buildings, the basement lacks vaulted or decorative elements and extends through the same footprint of the upper levels. From a structural perspective, the building shows adequate performance in bearing vertical loads, allowing to primarily focus on resistance to lateral forces. The height of the masonry cutting level was chosen after evaluations based on the geometries and on the significant presence of system facilities hooked to the ceiling of the basement. Another binding factor is the position of the devices, which is conditioned by the overlying masonry: it is essential that its compression state wouldn’t be altered. The project was entrusted by the Interregional Provveditorato of Tuscany, Marche, and Umbria based in Ancona, through an open tender, to the RTP, led by the engineering company Acale Srl of Ancona, which is handling architectural and structural design. Acale Srl was supported by Eng. Giorgio Giacomin of the GP Intech Group Div. Hirun International in the identification of the most suitable seismic devices among those available on the market, choosing a system composed of elastomeric isolators and slides. This article presents the crucial aspects of the design process.