PSI - Issue 44

Maria Teresa De Risi et al. / Procedia Structural Integrity 44 (2023) 958–965 De Risi, Del Gaudio, Scala, Verderame/ Structural Integrity Procedia 00 (2022) 000–000

960

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in a 30×50 cm 2 cross-section, whereas column sections vary from a minimum of 30×30 cm 2 (for most of the columns) to a maximum of 30×40 cm 2 (for central columns of the first floor only). Rectangular columns are always oriented in the longitudinal direction. About the assessment phase of these buildings, mean values of concrete compressive strength (f c ) and reinforcing yielding strength (f y ) have been assumed equal to 20.0 MPa and 320 MPa, respectively, according to suggestions by Masi et al. (2014) and Verderame et al. (2012) for the assumed steel typology and time period. These two buildings were designed for gravity loads only. Thus, they could be located in (the centroid of) each municipality in Italy classified as “not-seismic” before ’70. Fig. 3 shows these sites with their current seismic hazard expressed in acceleration (a g ) on stiff soil with 10% probability of exceedance in 50 years (Fig. 3a) and their more frequent soil typology according to Mori et al. (2020) (Fig. 3b), based on which the site effects are assessed in what follows. A plan topography is always assumed.

X

Longitudinal exterior frame

Z

3

4

5

6

1

2

400 300 400

Longitudinal interior frame

10

11

12

9

7

8

Transverse frame

15 16

17

18

13

14

23

24

21 22

19

20

400

400

300

400

400

(a)

(b) Fig. 2. a) Plan view; b) 3D view of the two selected case-study buildings.

Fig. 3. a) a g (in g) with 10% of exceedance probability in 50 years (rigid soil) in the centroids of each Italian municipality according to D.M. 2018; b) soil type (adapted based on Mori et al, 2020) 3. Code-based assessment of as-built buildings The first step of this work is the code-based assessment of the “as-built” case-study buildings according to the Italian code (D.M. 2018) via pushover analysis within the N2 framework (Fajfar, 2000), as explained in this section.