GNGTS 2018 - 37° Convegno Nazionale

382 GNGTS 2018 S essione 2.2 • Danno incondizionato, danno condizionato: valori del danno calcolati per il singolo comune; • Rischio incondizionato, rischio condizionato: valori del rischio calcolati per il singolo comune; • Scenario di danno, scenario di rischio: valori dello scenario per il singolo comune. La piattaforma presenta, come illustrato, molte funzionalità ed è estremamente flessibile in quanto consente all’utente di personalizzare il calcolo in merito ad esposizione, vulnerabilità, fragilità e rischio. L’unico elemento del calcolo fisso è l’input sismico costituito, come detto, da MPS04. La piattaforma inoltre permette la condivisione delle mappe con altri utenti. Riconoscimenti. La piattaforma IRMA è stata realizzata con il contributo finanziario della Presidenza del Consiglio dei Ministri – Dipartimento della Protezione Civile. Bibliografia D.M. 14.01.2008: Approvazione delle nuove norme tecniche per le costruzioni. G.U. 04.02.2008 n.29. Grünthal G.; 1998: European Macroseismic Scale 1998 (EMS 1998) . Council of Europe, Cahiers du Centre Européen de Géodynamique et de Sismologie, 15. OPCM n.3519 del 28.04.2006: Criteri generali per l’individuazione delle zone sismiche e per la formazione e l’aggiornamento degli elenchi delle stesse zone . G.U. 11.05.2006 n. 108 THE PHYSIOLOGICAL VARIATIONS OF THE DYNAMIC BEHAVIOUR OF STRUCTURES OVER TIME S. Castellaro Università di Bologna, Dipartimento di Fisica e Astronomia, Bologna, Italy Comparing the dynamic behaviour of a structure before and after an earthquake can provide quantitative information about the damage suffered from the structure during the event. As long as the structure is monitored continuously, the comparison of the pre- and post-event dynamic behaviour should be straightforward. However, at the present, many structures are tested only at a specific time in their life and are possibly re-tested after years or after relevant events. In the latter case, one has to be sure that the observed variations – if present – are caused by the investigated event and not by other causes. When attempting to assess the health of a structure, it is therefore mandatory to establish what is the physiological behaviour of the structure and what deviates from this behaviour. Any direct mass and stiffness variation have an effect on the dynamic behaviour. However, also ‘indirect’ stiffness variations, as those induced on the material properties by thermal fluctuations, show up in the dynamic behaviour. Here we focus on the latter. The elastic modulus of standard construction materials (concrete and steel) correlates negatively with temperature: i.e., it decreases while temperature increases (with relevant effects at the common environmental temperatures in the case of concrete, and less evident effects for steel). According to the CEB-FIP Model Code 1990: Design Code (1993) a common (for the temperate areas) summer-winter 20°C variation would lead to a variation in the Young elastic modules of standard concrete of approximately 5%, which stands for an eigen-frequency variation of approximately 2%, being the frequency proportional to the square root of the stiffness. This has effectively been reported for simple beams exposed to different temperature by Liu et al. (2016). This should also stand for a negative correlation between frequency and temperature for the final structures. However, the results published so far in the literature are apparently less