PSI - Issue 11

Sonia Boschi et al. / Procedia Structural Integrity 11 (2018) 169–176 Author name / Structural Integrity Procedia 00 (2018) 000–000

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Fig.6. Civitali complex: individuation of the different types of masonry and horizontal elements. (a) ground floor; (b) first floor.

3. SU identification and structural behavior

Based on the essays, the experimental investigations and mainly on the critical reading of the structural plants and construction details, different structural units have been pointed out, as reported by Fig. 7, over the ground and the second floors. The static and seismic safety evaluation of the complex has been assessed for each unity separately (Fig. 8b); however, a global model of the whole building complex has also been used (Fig. 8a) - mainly to perform the modal analysis. The evaluation of the safety assessment of the structures has allowed to highlight the main structural deficiencies, in relation to both the static and seismic actions. In particular, the analysis has been focused on: (i) static loads verification with reference to both the Serviceability and Ultimate limit states of some vaults, steel/wooden slabs and vertical masonry panels; (ii) seismic verification, accounting for the check of local mechanisms and global behavior. Numerical models have been implemented into commercial structural softwares and: (i) non-linear static analyses for equivalent frame models have been used for the analysis of the complex and each structural units; (ii) linear dynamic analyses with a finite element model have been used for the San Nicolao Church. Vertical masonry panels in the original portion of the building complex have shown a good static behavior and met the requirements of the Italian Building Code. Conversely, the panels located at the ground floor (East portion), made up of mixed stone/brick masonry have shown an unsatisfactory response following conventional checks methods. Indeed, they have low mechanical resistances, in certain cases significant slenderness and are subject to high loads as the structure has been raised by one floor. Nevertheless, for these walls, checks on the Serviceability Limit State are satisfied being in line with the absence of a crack pattern due to excessive compressive loads. Some numerical analyses have been conducted on six vaults taken as representative of all the types of vaulted structure of the building complex. For these analyses, the finite element code Mady developed ad hoc for the static and dynamic analyses of masonry structures, has been used (Lucchesi et al. 2017). The numerical analyses have allowed to perform the structural safety assessments of the vaults. In particular, the load multiplier that leads to collapse has been evaluated and assumed as a safety factor. It is wort noting that the safety assessment has been carried out for the Ultimate Limit State and, only for cases where safety requirements have not been achieved, the structural analyses have been performed with reference to the Serviceability Limit State, with the aim of investigating the actual behavior of the vault, in terms of deformations and trends of the stress state.