PSI - Issue 44

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Marco Peroni et al. / Procedia Structural Integrity 44 (2023) 1148–1155 M. Peroni et al./ Structural Integrity Procedia 00 (2022) 000 – 000

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Since our palace is a building construction dating back to the 17th century, providing a detailed picture of what the layout of the building was is an arduous task, not only at the level of the available documentation, but also because of the renovations and various alterations that have taken place over the centuries. The main body of the building, characterized by a wall box composed of varying thickness (from 35cm to 100cm), has a regular plan shape, maximum footprint in plan of about 85.00x11.00m and development in elevation on three above-ground floors and 2 more that go to define the side towers, for a maximum height at the eaves h=14.00 and h=22.3 at the eave line of the towers. There are no basement levels. By means of a site inspection, structural surveys, active damage mechanisms, and various cognitive assays were carried out to identify the different structural types, vulnerabilities, and any other interventions carried out over time. The first and second slabs are made of masonry barrel and pavilion vaults covering spans ranging from 4.50m to 6.50m; in addition to the lightweight concrete filler (ISOCAL 400kg/mc), there is a 5cm thick reinforced concrete slab reinforced with electro-welded mesh. The roofing slab is composed of brick panels warped parallel to the ridge line. The replacement of the old roofing slab with the new roofing was carried out around the 1970s/80s. A series of “in situ” surveys at the top of the top floor perimeter confirmed the presence of reinforced concrete perimeter beam with 4 ϕ 10. In the same years in which static improvement was done at the level of the inter-floor floors (mezzanine level), we also focused about the Palace's foundations, which consisted of surface-type foundations characterized by the enlargement of the wall section of the walls on the ground floor. Regarding interventions at the foundation level, an earthquake-resistant consolidation was then carried out, which included the construction of reinforced concrete curbs on both sides with through-grafts. On the bank side of the Lamone River, there are two loggias with plan dimensions of 13.50x2.70m and development in elevation on a single above-ground floor. The columns are made of bricks according to a certain modular construction scheme, while the floor slab is made of masonry cross vaults. These porches, dating back to the 1700s, were the subject of provisional static support intervention (shoring) in the 1990s by the Soprintendenza dei Beni Artistici e Culturali di Ravenna. The intervention, as shown in the photographic drawings, involved the installation of metal support elements, which transfer the loads arising from the masonry structure in elevation to the foundation soil through a specially made foundation slipper. The masonry columns (about 60x60 cm on a side) of the porches are thus almost unloaded in the face of the advanced state of deterioration that can also be deduced from a preliminary visual analysis. 3. Seismic retrofitting works As we mentioned, it was not necessary to revolutionize the wall structure of the building to improve it seismically but only to intervene in those weaker and more vulnerable parts that could have an effect on the stability of larger parts of the building. A first part of the intervention consisted of the insertion of two large metal frames in the entrance hallway that allowed (drawing inspiration from a seventeenth-century map that envisioned the establishment of a kind of cruciform transept to connect the hallway with the two side porches) to reopen the spaces of that large central entrance hall.