Recent northeast Italian tornado events: lesson learned for improving structures

Increasing intensity and frequency of tornadoes have been reported in Europe in the last decades, and in Italy, in particular in the northeast area, including Veneto, Friuli Venezia Giulia and Trentino Alto Adige. The public consciousness and the meteorological control of this risk are sufficiently established in the USA. The European continent and the northeast of Italy do not exhibit a similar state, although the tornado damages induced are increasing and becoming of economic relevance. Studies and research are diffused and have reached a detailed level, being able to correlate tornado intensity to a detailed damage state for a wide amount of building classes. But, codes and standard, both in USA and in the whole European continent, have not been developed for tornado loadings. For this reason, to fill the gap between studies, research and observational data, in this study Italian wind extreme events are presented and discussed first. In a second part, the damage assessment results of the most extreme events recorded in the northeast of Italy (from F3 to F5, Fujita scale) from 1905 to 2017 are presented. Codes and standard showing the lack of design and verification procedure are presented in the third part. Finally, a tornado-resistant building classification is presented to enforce the consciousness that new codes and standard could protect people from extreme events, decreasing dramatically the devastation of not so rare phenomena also for Italy.