Vertical Addition of a Public Masonry Building by a Cold-Formed Steel Structure

In recent years, the concept of sustainable development has gained prominence due to the growing inadequacy of energy production to meet consumer demands without impacting quality of life. The construction sector plays a significant role in this issue, as it is a major source of environmental impact. In response, policies focused on energy reduction emphasize the redevelopment of existing buildings to improve their energy efficiency. This context has also highlighted the challenge of finding living space in cities, especially in historic Italian city centres, where population growth is rapid. To address these challenges, economic and environmental solutions are needed to integrate the preservation of existing architecture with modern requirements. Vertical addition, as an alternative to traditional urban expansion, offers a viable solution. Recent Italian regulations support such initiatives, and this paper explores the structural behaviour of a public masonry building of Southern Italy subjected to vertical addition using cold-formed steel technology. The study first presents the design approach using a steel stick-built construction, then demonstrates its effectiveness in adding stories to the existing structure with minimal reinforcement, as verified through static non-linear analyses. Based on the numerical results, the vertical addition steel structure is successfully erected, marking a pioneering application of a lightweight, sustainable steel system to increase living units in Italian historic centres.