PSI - Issue 44

Paola Sorrentino et al. / Procedia Structural Integrity 44 (2023) 1308–1315 Paola Sorrentino et al. / Structural Integrity Procedia 00 (2022) 000–000

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4.1. Linear static analysis

Preliminarily, to assess seismic vulnerability of the case study, a linear static analysis has been carried out to investigate the seismic behavior of the structure. At first the periods in the two orthogonal directions have been evaluated. In particular, the Italian Building Code in the case of linear static analysis defines the period as follows: * = √2 with: = elastic lateral displacement of the highest point of the building, expressed in meters, due to the seismic weight applied in the horizontal direction. Consequently, in x and y direction, the periods are equal to 2.08s and 0.74s, and the elastic displacements correspond to 1.08m and 0.14m in x and y direction, respectively. As static equivalent force, it has been considered a base shear . equal to 4.5% and 6.8% of the seismic weight of the structure in x and y direction respectively, properly derived from the design spectra. In Figure 2 the Elastic and Design Acceleration Spectra for the Olympic Village in Rome with the spectral accelerations in x and y direction are shown.

0.40

Elastic Spectrum Design Spectrum (q=2.88) Design Spectrum (q=1.5)

Sa [g]

0.30

Tx Ty

0.20

0.10

0.068

0.045

0.00

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

T [s]

Figure 2. Acceleration Spectrum.

The adopted distribution of inertial force has been defined as follow: / = . / / ∑ 4 4 (2) where / is the inertial force applied to the i-th floor, . is the base shear, / and / are respectively the weight and height of the i-th floor. In Table 2 weights and inertial forces are listed. Table 2. Weight and inertial forces defined for linear static analysis Floor Infill Beams Columns Stair W Fx Fy [kN] [kN] [kN] [kN] [kN] [kN] [kN] [kN] I 4,197 331 798 607 219.70 6,153 55.28 135.00 II 4,197 331 798 472 165.87 5,964 100.19 244.66 III 4,197 331 798 349 165.87 5,841 143.77 351.07 IV 4,197 331 798 201 165.87 5,692 184.58 450.74 V 3,336 222 798 66 103.15 4,526 182.13 444.75 Sum 20,12 1,548 3,990 1,696 820 28,18 665.95 1,626.22 In view of a preliminary evaluation of building seismic vulnerability, the stresses obtained by applying the 32 combinations have been considered. In in particular, axial force 67 and bending moment 67 have been compared