Issue 51

M. Guadagnuolo et alii, Frattura ed Integrità Strutturale, 51 (2020) 398-409; DOI: 10.3221/IGF-ESIS.51.29 404 Latitude Longitude V N Use Class C U Site Class a g Palazzo Petrucci Novelli 41.188625 13.976842 50 years II 1 A 0.098 g Palazzo Ducale 41.365277 14.383055 50 years II 1 A 0.249 g Table 1 : Values of seismic parameters. “Palazzo Petrucci Novelli” The structure is composed by three different levels; the first one has steel floors and several vaults, the second one has steel and timber floors, while the roof consists of timber structures. The corresponding loads at each level are summarized in the Tab. 2. Level Dead loads: G k Live loads: Q k Masonry Weight 1° 12 kN/m 2 2 kN/m 2 16 kN/m 3 2° 6 kN/m 2 2 kN/m 2 16 kN/m 3 3° 1.7 kN/m 2 2 kN/m 2 16 kN/m 3 Table 2 : Values of loads and masonry parameters. The confidence factor F C assumed is equal to 1.35 (corresponding to complete survey of the building geometry but limited knowledge of material mechanical properties). In this case the shear strength is equal to 0.028 MPa while the failure coefficients related to the type of failure expected in masonry piers (Cp= ௜ ) and the resistance of spandrel beams (Cs= ௜ ) are assumed equal to 0.8. According to the procedure provided in [14] for “Building Structures”, a minimum safety index I S (minimum between I SP and I SA ) equal to 0.45 has been computed. Therefore, the building is not capable to withstand the design earthquake. “Palazzo Ducale” The confidence factor F C is equal to 1.35; the shear strength is equal to 0.028 MPa and Cp and Cs have been also assumed equal to 0.8 in this case. Based on the above data, the smaller safety index is equal to I S = 0.25, indicating that the structure is unable to withstand the seismic forces provided by the seismic code. Level Dead loads: G k Live loads: Q k Masonry Weight 1°- 2° - 3° 5.4 kN/m 2 2 kN/m 2 19 kN/m 3 4° 0.5 kN/m 2 2 kN/m 2 19 kN/m 3 Table 3 : Values of loads and masonry parameters S ELECTION AND O PTIMIZATION OF I NTERVENTIONS he procedure aims at locally strengthening the buildings and increasing their seismic safety index. The choice of retrofit interventions must be based on a motivated strategy aimed at involving only selected building elements to be reinforced to improve structural performance. Through the simplified procedure provided by the Italian Guidelines for the evaluation and mitigation of seismic risk of cultural heritage and following the examples of this paper it is possible to identify the weakest level of a generic building