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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The evolution of plastic hinges shows that at collapse the structure exhibits a global mechanism with plastic hinges at the ends of the beams and at the base of the columns on the ground floor and the plastic hinges of the stair beams reach the ultimate rotation (Figure 6).

Low damage

Severe damage

Collapse

(b)

(a)

Figure 6. Evolution of plastic hinges in (a) x direction and (b) y direction.

These results confirm what has been obtained through the preliminary assessment of the seismic vulnerability carried out with the linear static analysis: the structure has its own capacity to horizontal loads, even if designed only to gravity loads. 5. Conclusion In this paper the seismic vulnerability of a R.C. building of the Olympic Village of Luigi Moretti in Rome has been investigated. It is a representative case of gravity-load design for R.C. buildings, dating back to 1960s, built in low seismic areas and respectful of the “five points of modern architecture” by Le Corbusier. Linear and nonlinear static analysis have been carried out for the evaluation of building seismic vulnerability. Considering the structure at the current state, the presence of frames, having a single span 8m-long, leads to have columns with high normal stress values, with a consequent low eccentricity. Being located in a low seismic area, the inertial forces are modest and consequently the bending moments due to the seismic action are low. Furthermore, since the structure has frames only in y direction, in x direction the structure has low stiffness and low period; for this reason, seismic forces in the x direction are very moderate. Results from linear and nonlinear static analysis show that, despite the structure has been designed to bear only gravity load, it shows a certain capacity to counteract also seismic forces. Future research will be devoted at investigating if Fajfar simplified method is adequate to assess the seismic vulnerability of the structures, considering that the demand in terms of displacement, shown by recent earthquakes, is certainly higher than the one obtained with this method. Furthermore, a structure with frames arranged only in transversal direction can result adequate to counteract seismic action for its low stiffness, having a high capacity in terms of displacements. Acknowledgements The support provided by consortium ReLUIS is acknowledged. The activities are related to the topics of WP5 “ Interventi di rapida esecuzione a basso impatto e integrati ” e and W15 “ Isolamento e dissipazione ”, included in the project DPC-ReLUIS 2019-2021. Thanks to Prof. Luca Lanini for his precious contributions in the survey. References CSLLPP (Consiglio Superiore dei Lavori Pubblici). D.M. 17 gennaio 2018 in materia di “norme tecniche per le costruzioni”. Gazzetta Ufficiale n.42 del 20 febbraio 2018, Supplemento ordinario n.8, Ministero delle Infrastrutture e dei trasporti, Roma; 2018, in Italian Iervolino, I., Galasso, C., Cosenza, E., 2009. REXEL 2.31 (beta) e la selezione normativa dell’input sismico per l’analisi dinamica non lineare delle strutture. In: XIII Convegno ANIDIS Parisi, M.A., Maggio, E., Marini, C., Sumini, V., 2013. Edifici in calcestruzzo armato in zona sismica: valutazione delle risorse. In: XV Convegno ANIDIS Padova Buzzi L. Il cemento per le Olimpiadi. In: Industria italiana del cemento. Anno XXX, 10, Ottobre. Fajfar, P., 1999. Capacity Spectrum Method based on inelastic demand spectra. In: Earthquake Engineering and Structural Dynamics 28, 979-993 Fajfar, P., 2000. A Non Linear Analysis Method for Performance Based Seismic Design. In: Engineering Spectra, Vol. 16, No.3, 573-592