PSI - Issue 78

Giuseppe Brandonisio et al. / Procedia Structural Integrity 78 (2026) 2162–2168

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2.4. Seismic Vulnerability assessment The results of the pushover analyses are summarized in the following paragraph: eight pushover curves are showed in Fig. 4, each one corresponding to a single seismic loading case, namely: Pushover1=Mode X+; Pushover 2=Mode X-; Pushover 3=Mode Y+; Pushover 4=Mode Y-; Pushover 5=Mass X+; Pushover 6=Mass X-; Pushover 7=Mass Y+; Pushover 8=Mass Y-. The seismic vulnerability indexes ξ E,SLV are summarised in Table 1and of Fig. 5.

Fig. 4 Pushover curves for the analysed FEM models

The combinations with the distribution of seismic forces proportional to the modes of vibration (combinations 1÷4) are more burdensome than combinations 5÷8 of forces proportional to the masses. For the global AS-IS and Complete models, similar and increas ingly burdensome results are observed (ξ E,SLV smaller) of the individual isolated bodies. Considering the displacement capacities (dRd) of the global models are similar to those of the individual bodies, this is due to the greater displacement demands (dEd) measured on the global models because they are more deformable in both directions of the building. Table 1 Comparison of the Seismic Vulnerability Indexes

ξ E

Combination

As-Is Global Model

Completed Global model

A

B

C

1

2

3

1 Mode X+

1.27 1.28 1.26 1.28 1.46 1.47 1.43 1.45 1.21 1.47

0.90 0.91 0.67 0.75 1.00 1.04 1.01 0.88 0.67 1.04

0.76 0.74 1.23 1.25 1.01 0.99 1.54 1.58 0.74 1.58

1.24 1.28 0.90 0.83 1.50 1.67 1.38 1.30 0.83 1.67

0.95 1.11 0.86 0.99 1.22 1.53 1.04 1.20 0.86 1.53

0.84 1.17 1.26 1.18 1.06 1.47 1.65 1.50 0.84 1.65

0.62 0.68 0.64 0.62 0.85 0.89 0.82 0.81 0.62 0.89

0.64 0.64 0.65 0.68 0.83 0.82 0.88 0.89 0.64 0.89

2

Mode X-

3 Mode Y+

4 5 6 7 8

Mode Y- Mass X+ Mass X- Mass Y+ Mass Y-

Max Min