PSI - Issue 44

Stefano Bracchi et al. / Procedia Structural Integrity 44 (2023) 442–449 Stefano Bracchi, Maria Rota, Andrea Penna / Structural Integrity Procedia 00 (2022) 000–000

444

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mechanical properties of masonry were obtained from characterization and in-plane cyclic tests (Magenes et al. 2010). Table 1 reports the values of mechanical properties adopted in this work, together with the material properties of diaphragms (Table 2).

North

West

South

East

Fig. 1. Façades and floor plans of the case studies (adapted from Magenes et al. 2014).

Table 1. Masonry mechanical properties (adapted from Penna et al. 2016). Compressive strength f m (MPa) Young’s modulus E (MPa) Diagonal shear strength f tu (MPa)

Shear modulus G (MPa)

Mean

3.28 0.26 8.0%

2537 378.7 14.9%

0.138 0.030 22.1%

841

St. Dev.

141.5 16.8%

C.o.V.

Table 2. Masonry mechanical properties (adapted from Penna et al. 2016). Building Floor level E 1 (MPa) E 2 (MPa)

G 1,2 (MPa)

2

1, 2

18500 30000 21800

8000

750

1 2

30000 11800

12500 10000

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When modeling the buildings with equivalent-frame technique, two geometric discretizations were considered, a standard discretization (STD) and a configuration with modified geometry (MOD). The first one better accounts for the piers deformability but it underestimates the capacity of the structure with respect to the second one, in which the geometry of structural elements is based on the minimum clear height of the adjacent openings. This second geometry was adopted to better replicate the failure mechanism and damage observed during the experimental tests. In this work, buildings were modelled using the bilinear element (Lagomarsino et al. 2013) compliant with MIT (2019). The adopted shear strength criterion is the one proposed by Turnšek and Sheppard (1980), with the value of f tu given in Table 1. With respect to the other macroelements used in this work, in this case it is necessary to halve the elastic moduli E and G to account for cracked stiffness.