PSI - Issue 78

Maria Eleonora Pipistrelli et al. / Procedia Structural Integrity 78 (2026) 1911–1918

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springs simulating adjacent structures, and the unit modeled with a limited portion of neighboring S.U.s. The aim is to evaluate how model boundary conditions influence seismic response and to provide practical guidance for the vulnerability assessment of masonry aggregates in historic urban environments.

2. The case study The portion of the masonry aggregate selected for this study corresponds to the north-east corner of the building currently housing the Istituto Tecnico Agrario Augusto Ciuffelli in Todi. Fig. 1 presents both a picture of the aggregate (Fig. 1-a) and a 3D model of the building (Fig. 1-b), where the portion under investigation is highlighted with a dashed red circle. The aggregate is characterized by a cloister-type layout, distributed across several staggered levels, and built primarily in masonry.

Figure 1: (a) view of the aggregate; (b) 3D model of the building, with the analyzed north-east corner marked in red.

2.1 Historical overview The historical development of the agricultural institute can be divided into five main phases. The first began with the foundation of the monastery in 1248. The current building retains the typical rectangular monastic layout, centered around a cloister. Structural buttresses on the eastern block were a common feature in other monastic buildings in Todi. A key original element, the church's bell tower, is absent today. The second phase started in 1786, when the monastery was suppressed and its functions were gradually replaced by those of the nearby hospital. After the monastery’s suppression in 1786, renovation works began to adapt the structure for hospital use, continuing through the late 18th century. However, by the century’s end, the complex was largely abandoned due to structural failures caused by landslides and soil instability. The most significant changes during this phase included new workshops and annexes built on the southern side, adjacent to the church. The third phase began in 1883, when the site was transformed to host the Practical School of Agriculture. During this transformation, the church was likely raised by an additional floor, and a new western wing, now home to the school’s administrative offices, was added. The fourth phase unfolded in the early 1900s, with a series of renovations to accommodate a growing student population. During this phase, the complex began to resemble its current form, except for the western side, which continued to evolve in later years. In 1933–1934, the school officially became the A. Ciuffelli Agricultural Technical Institute. The final structural additions were completed by the end of the 20th century, solidifying the layout we see today. All the phases of the aggregate expansion are schematically represented in Fig.2-a, using different colors over the current rooftop view.