PSI - Issue 44

Giacomo Lazzerini et al. / Procedia Structural Integrity 44 (2023) 163–170 Giacomo Lazzerini et al. / Structural Integrity Procedia 00 (2022) 000–000

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4

3.2. Parameters included in the numerical models

To develop the building numerical models, eight parameters were considered, whose variability was carefully chosen to make models representative of the actual buildings in the investigated area. Specifically, the following parameters were varied: 1. building height (number of floors): three- or four-storeys 2. type of material on the ground floor: disorganized irregular stone or roughly cut stone with good texture (highlighted in red in Table 2) 3. type of material on the upper floors: disorganized irregular stone or roughly cut stone with good texture (highlighted in red in Table 2) 4. percentage of openings on the ground floor 5. percentage of openings on the upper floors 6. floor stiffness: rigid or deformable floor 7. thickness of internal walls: t=12cm (single-headed brick wall) or t=24cm (double-headed brick wall) 8. loads: loads prescribed by NTC (2018) or increased by 1.00 kN/m 2 Table 2: Table C.8.5.I from Circolare (2019) with mechanical parameters of existing masonry building

f m

t 0

f v0

E

G

W

Masonry type

(N/mm 2 )

(N/mm 2 )

(N/mm 2 )

(N/mm 2 )

(N/mm 2 )

(kN/m 3 )

Disorganized irregular stone (pebbles, erratic and irregular stones) Barely cut stone, with leaves of uneven thickness (*) Roughly cut stone with good texture Irregular soft stone (tuff, limestone, etc.) Ashlars of soft stone (tuff, limestone, etc.)(**)

1.0 – 2.0

0.018 - 0.032

--

690 - 1050

230 - 350

19

2.0

0.035 - 0.051

--

1020 - 1440

340 - 480

20

2.6 - 3.8

0.056 - 0.074

--

1500 - 1980

500 - 660

21

1.4 - 2.2

0.028 - 0.042

--

900 - 1260

300 - 420

13-16 (**)

2.0 - 3.2

0.04 - 0.08

0.1 - 0.19

1200 - 1620

400 - 500

13-16 (**)

Stone square blocks

5.8 - 8.2 2.6 - 4.3

0.09 - 0.12 0.05 - 0.13

0.18 - 0.28 2400 - 3300 800 - 1100

22 18

Bricks and lime mortar (***) Hollow bricks with cementitious mortar (e.g., holes <= 40%)

0.13 - 0.27 1200 - 1800

400 - 600

5-8

0.08 - 0.17

0.2 - 0.36

3500 - 5600 875 - 1400

15

Note: Red lines refer to masonry of the ground floor (red), while green lines refer to the upper floors (green)

The variability range of parameters 4 and 5 was chosen from the results of the morphological analysis. As shown in Fig. 3 on the longer side of the building, a percentage of openings varying between 30% (Low opening rate) and 60% (High opening rate) was considered for the ground floor and between 20% and 40% for the upper floors; on the shorter side of the building, a flat-rate percentage of 20% was assumed for all floors.

Fig. 3: Opening rate considered within numerical models Concerning models derived from known geometries (point A section 3.1), three “index” buildings were considered: building A, building B and building C. All of them are characterized by a gable roof (Fig. 1), but in the numerical model, the roof has been modelled as flat considering a higher height of the last storey to consider the presence of gables.