In the framework of project applications for seismic improvement and retrofitting of existing masonry structures with notable historical and architectural significance, the ongoing design project of the "Palazzo del Governo" in Livorno applies a retrofit solution through base seismic isolation.

The project was entrusted by the Interregional Provveditorato for Public Works 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 specifically handling the architectural and structural design.

The rationalist building, built between the 1930s and 1940s, occupies an entire block. It houses strategic offices such as the Prefecture and the Police Headquarters of Livorno, as well as 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. In particular, the building is independent on all sides, the basement lacks vaulted or decorative elements (having been used mainly as shelter for tools and storage area) and extends through the same footprint of the upper levels, which is particularly advantageous for this type of work. From a structural perspective, the building shows adequate performance in bearing vertical loads, allowing designers to primarily focus on resistance to lateral forces.

The height of the masonry cutting level was chosen after numerous evaluations based on the geometries and on the significant presence of system facilities hooked to the ceiling of the basement.

Another strictly binding factor is the position of the devices, whose “step” is conditioned by the overlying masonry: it is essential that its compression state is not altered.

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, describing how to manage seismic retrofitting using isolators on a masonry building which is subject to monumental constraints and while maintaining the upper floors operational.