The "Emilia" earthquake: an overview of damages and collapses in industrial precast buildings

A series of earthquakes struck the Emilia region, in Northern Italy, in May 2012. Two main mainshocks, characterized by moment magnitudes of 6.1 and 6.0 were identified. The area struck by the earthquakes was not considered as seismic until a few years ago: only in 2001 an update in the Italian seismic hazard map assigned to that region a low to moderate seismicity, becoming mandatory for designers only in 2005. For this reason, most of the buildings that experienced the earthquake were designed without seismic criterion. As the region is one of the most productive in Italy, a high concentration of industrial precast buildings can be found and the ground-shaking resulted particularly severe for these structures. In the paper, an overview of the damages and collapses caused by the earthquake on precast industrial buildings is given. Extensive field surveys took place immediately after the shocks, enabling the authors to observe and collect a vast amount of data on damages of these buildings. They were very vulnerable for several reasons. The absence of connections between the various precast monolithic elements was the main cause of most collapses. The inadequacy of connection of external precast walls to the bearing elements and the interaction between non-structural walls and structural elements were also critical aspects in many cases. For recently designed industrial buildings, the inadequacy of columns and foundations was responsible of very serious failures. Finally, some collapses were related to the overturning of metallic shelves not designed to sustain horizontal actions.