Enhancement of seismic performance of historical clustered buildings

The assessment of the seismic vulnerability of unreinforced masonry buildings, particularly those in historic city centres, is crucial for preserving Europe’s architectural heritage. However, evaluating these structures, which represent a significant portion of the existing building stock, remains challenging due to limited data on their geometry and structural details, shaped by centuries of unregulated urban development. Additionally, these buildings often exhibit thermal inefficiencies due to the use of materials with low insulating properties. This study investigates the seismic behaviour of a typical unreinforced masonry building complex placed in the historic centre of Mirandola, severely affected by the 2012 Emilia–Romagna earthquake. A parametric approach is employed to analyse the influence of key structural factors—including material type and knowledge level—on seismic performance of the masonry aggregate. Numerical simulations are conducted both before and after the implementation of an innovative seismic-energy retrofit system, which combines an aluminium alloy exoskeleton, designed for seismic reinforcement, with sandwich panels, aimed at reducing thermal losses. The primary objective is to quantify the impact of these factors on the building’s structural performance. Static non-linear analyses and a fragility assessment are carried out to identify the most influential parameters affecting the seismic behaviour of the building aggregate. The achieved findings highlight the critical role of detailed structural knowledge, particularly regarding masonry quality and amount of available data, in predicting the building’s seismic performance. Furthermore, the proposed integrated seismic-energy solution significantly reduces vulnerability, demonstrating to be a sustainable and effective strategy for preserving the structural integrity and energy efficiency of historic masonry buildings.