PSI - Issue 29

Michele Paradiso et al. / Procedia Structural Integrity 29 (2020) 63–70 Paradiso, Conte and Prosperini / Structural Integrity Procedia 00 (2019) 000 – 000

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improvement of the complexwith the recovery of the internal spaces and the fundamental reconstruction of the roof. Through the visual and photographic examination, developedduring the investiga tionphases, thefamilies of injuries and the phenomena of instability that characterize the artefactwere determined. This macro family of cracks, present in rela tion to the original openings, a llowed to validate the historical-archival investigations conducted in the first phase of knowledge and to reconstruct the original layout of the Augustinian church fromwhat exists today. On the longitudinalwa lls, a t the bottom, there are injuries in a diagonal direction at the right and left corners of thefaçade. The cause can be a ttributable to a sliding or settling of the centra l part of the building, in rela tion to the high deformability of the bearing ground. The analysis carried out in the choir area led to the division of the lesions into three groups. Afirst family of injuries are founda long thewa ll of therear façadeprobably causedby the thrust of the arch of the central chapel. The second family of lesions is loca ted on the samewa ll a t the corner, presumably due to the thrust of the roof vault and the third family is loca teda t the side wa lls in the lower part of the choir, causedby the overturningof therear façade. 2.1. Structural analysis After carrying out the preliminary and preparatory analyses (characterization of the ma terials, analysis of the mortars, geognostic investiga tions, ca lculation of the pretension of the tie rods), we moved on to modeling and defining the specific loads andweights of thematerials to proceedwith the analysis of thestatic response linear using the Strauss7 software. Each element of the structure, metal profiles and wooden beams, has been reproduced in the form of a linear beamelement with which a specific property is associated. For the materia l characteristics, the internal software library was used, modifying the coefficients to reproduce the qualities of the historicalmaterial. The most stressed area is certainly the rear facade and the counter-façade which have a noticeably grea ter vertical displacement than the other areas. This area corresponds to the apsidal part which is, in fact, chained both in the longitudinal and transversal direction. These settlements are due to the characteristics of the underlying soil. The ca lculationof the maximumdisplacements generatedby the permanent covering loads highlights howthis produces a loweringof the central part of the truss chains. This is certa inly due to the large span they must cover (about 20 m.) And the connectionof the truss heads to theconcrete curb inserted by the works carried out by the Soprintendenza in the 1990s. As for the transversepartitions, suitably loaded in the model bothby theweight of the roof andby that of the floor on the top floor, they donot showsignificant displacements in the center; while, in correspondence with the a ttachment to the perimeter wa ll, there are vertical displacements. The results of the dynamic analysis carried out, consideringa design earthquakeof magnitude 4.5, highlightedareas of intrinsic weakness of thestructure of not high gravity: analyzing the first combination, which provides for a transverseseismic action to the longitudinalwa lls, it is founda state of crisis of the la tter in the central area. The cause is due to a bador insufficient tighteningof the trusses to the perimeterwalls. Ana lyzing the secondcombinationwith a seismic action longitudinal to the building, the areas tha t are most stressedare thoseof the transverse partitions and the upper part of the internal counter-facade.

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Fig. 4. (a) Vertical displacements along the z axis, representation by chromatic maps of the model of the Church, from Red (more compressed) to Blue (less compressed); (b) Result of the dynamic analysis, combination 1: earthquake in the longitudinal direction, combination 2: earthquake in the transverse direction.