Building pathologies. Analysis of three case studies Michela Monaco 1 , Immacolata Bergamasco 2 , Antonino Iannuzzo 3 , Antonio Gesualdo 4 , 1 University of Sannio, Benevento, Italy, monaco@unisannio.it 2 Ministry for Cultural Heritage and Activities and Tourism, Archaeological Park of Pompeii, Italy, immacolata.bergamasco@beniculturali.it 3 ETH, Zürich, Switzerland, iannuzzo@arch.ethz.ch 4 University of Naples “Federico II”, Napoli, Italy, gesualdo@unina.it Abstract: Masonry buildings are the main part of the Architectural heritage in the World. The need of preservation for the historical memory, together with the exigence of fruition and use, has evidenced the need of appropriate analysis tools. In general, the stresses in masonry structures are usually considerably lower than those required for their material failure, so that the stability is mainly due to their shape and self weight. These aspects allowed in the past the simple realization of construction models in a reduced scale in order to assess the stability. As the history has pointed out, the behaviour of constructions is strongly linked to the workmanship and the good realization of the construction details. Local or global collapse can occur in fact due to pathologies arising during the construction or to bad realization of construction details. This paper deals with this last aspect, examining three different masonry buildings: the first one is a brick masonry building in Bologna: San Barbaziano Church, the others are two Roman domus in two different archaelogical sites in Campania: Villa Regina (Boscoreale, Napoli) and Villa dei Misteri (Pompeii, Napoli). The defects have been divided into two classes: structural defects and non structural ones. It is shown that structural defects can cause a global damage and could involve significant interventions. Keywords: ancient masonry building; pathology. 1. Introduction Knowledge and understanding the damage and failure mechanisms of masonry structures are necessary to prevent catastrophic failures and enhancing effective restoration of historical masonry monuments. The optimum approach includes historical, experimental and numerical studies to achieve a good level of knowledge. There are in fact several aspects that should be examined before developing a restoration design (De Ponti et al., 2017). In particular, experience shows that a broader study of the monument, the history and architecture of the building, its material consistence and actual state are indispensable prerequisites for the successive analyses, in order to account for all initial and consecutive construction phases, previous interventions or additions (Bosiljkov et al., 2010; Asteris, et al., 2017). Furthermore, the results of the experimental investigations regarding geometrical data, the in situ evaluation of the materials mechanical characteristics (Monaco et al., 2021a and 2021b; Guadagnuolo et al., 2020a), the properties of the structural elements like masonry walls, arches, vaults and floors, the complex response of the construction to different possible actions, as well as the results of eventual previous monitoring can be crucial for reliable designing interventions on ancient structures (Monaco et al., 2014; Gesualdo and Monaco, 2015; Guadagnuolo et al., 2020b, 2020c). In the case of San Gimignano towers “...the construction is surprising, the method is based on very thick stone masonries and extraordinary mortars, with just a few 1193 https://doi.org/10.4322/CINPAR.2021.146