PSI - Issue 84

Manuel Capogna et al. / Procedia Structural Integrity 84 (2026) 717–724

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Fig. 2. (a) Mode 1 – 1,18s – plant view; (b) Mode 2 – 0,71s – plant view; (c) Mode 3 – 0,57s – plant view; (d) Mode 1 – 1,18s – side view.

The analysis of the ratios between the periods of translational and torsional modes confirmed the torsional vulnerability of the building. The presence of rigid stairwells in asymmetrical positions relative to the overall layout shifts the center of stiffness, inducing floor rotations that load the corner columns unevenly. This evidence underscores the importance of a seismic retrofitting intervention that aims not only at increasing local strength but also at regularizing the overall global dynamic response, possibly through the use of targeted reinforcements such as steel

jacketing (Gkournelos et al., 2021; Riyad S. Aboutaha, 1999). 5. Non-linear static analysis (Pushover) and safety assessment

To evaluate the seismic capacity of the Minervini-Sisti complex, a pushover analysis was conducted, the main results of which are summarized in Fig.3. The analysis was performed by applying two horizontal force distributions: one proportional to the masses (Group 1) and one proportional to the first vibration mode (Group 2), as required by the NTC 2018. The resulting capacity curves show the evolution of the base shear as a function of the displacement of the control point (located at the center of mass of the top floor).

Fig. 3. Capacity curves for Minervini-Sisti complex.