PSI - Issue 44

Devis Sonda et al. / Procedia Structural Integrity 44 (2023) 115–122 Devis Sonda et al. / Structural Integrity Procedia 00 (2022) 000–000

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where x takes a value from 1 to 4 according to the four conditions that describe the state of conformity of the structure. The four conditions of the structure (from i to iv ) correspond to the following percentages of conformity: 100%, 58.4%, 34.1%, and 16.8%. For precast elements connections and interference with non-structural elements, the increase in vulnerability is assumed to be significant only when following a high deviation from the ideal situation, and therefore a strong reduction in terms of absorbed energy only occurs in limited conditions. A polynomial trend is assigned to the proposed relation, which is assumed to be described by the function: 0 / . . (11) where x takes a value from 1 to 4 according to the four conditions that describe the state of conformity of the structure. The following percentages of conformity correspond to the four conditions (from i to iv ): 100%, 91.4%, 61.6% and 16.2%. The hypothesis assumed for the definition of the relationships, that describe how the parameters modify the energy area, are under calibration applying to real case histories of detailed vulnerability assessments carried out on structures. 4. SISMO-Fast case history As example of application of the SISMO-Fast methodology, a real case of an industrial warehouse with an office area located at the front, is presented. The structure has been designed not considering seismic actions, without connections between structural elements, and limited interferences with internal non-structural infill panels are present. The layout of the structure is shown below in Fig. 4, highlighting the areas of greatest rigidity, which corresponds to a double-level portion with reinforced concrete staircases, and the presence of a joint between the office area and the production area.

Fig. 4. (a) aerial view of the building; (b) plan scheme with high rigidity areas highlighted in red

The parameters that describe the conditions of the structure have been assumed to be: a) structural regularity: structure with irregularities on one side in the plan (34.1%); b) interference with non-structural elements: partial infills / interfering local irregularities (91.4%); c) column ductility: design for horizontal actions (wind) (34.1%); d) effective beam-column connections: absence of connections (16.2%). In the graphic representation of Fig. 5, the ratio between the areas, and therefore the ratio between the total energy of the existing structure and the new equivalent structure, is approximately 16%. Therefore, we can conclude that the structure has an extremely high vulnerability, compared to the same building designed according to the current code provisions for that seismic area.