Failure of industrial structures induced by the Emilia (Italy) 2012 earthquakes Laura Liberatore, Luigi Sorrentino ⇑ , Domenico Liberatore, Luis D. Decanini Department of Structural Engineering and Geotechnics, Faculty of Architecture, Sapienza University of Rome, Via Antonio Gramsci 53, 00197 Rome, Italy article info Article history: Available online 19 February 2013 Keywords: Damage assessment Disasters Joint failures Multi-site damage Structural failures abstract At the end of May 2012, a seismic sequence struck the Emilia Region of Northern Italy, with two main events of local magnitude M L 5.9 and 5.8. The area affected is characterised by a high density of industrial buildings and its seismicity has been codified only recently. Given these conditions, there have been many structural failures. In this study, damage observed during field surveys is presented focusing on production plants. The interpreta- tion of the structural performance is carried out recognising seven main types of damage related to: column base, short column failure, column top, shed beam, roof element, clad- ding/infill panel, and steel stand. These failures are compared with behaviours observed in the L’Aquila (central Italy), earthquake of 2009, with provisions compulsory at the time of the construction and with the current Italian seismic code. Some of the damage types, such as the formation of a plastic hinge at the base of a column and the unseating of the beam end from the column support, are interpreted by means of non-linear dynamic analyses on plane models representing typical configurations for such buildings. The contact between column and beam is modelled with either a pin or a friction connection. The analyses high- light the directionality of damage, the relevance of the vertical component of earthquake excitation, and the significant inelastic rotation induced in the columns. Finally, recom- mendations are made to improve the seismic behaviour of these types of structures. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction On May 20th, 2012, at 02:03 UTC (04:03 local time), Emilia region of Northern Italy (Fig. 1) was struck by an earthquake of local magnitude M L 5.9 [1]. The municipalities which suffered the highest damage are San Felice sul Panàro and Finale Emilia. Many other damaged municipalities are located in the districts of Modena and Ferrara. After the mainshock, several after- shocks occurred, two of which of magnitude M L 4.9 and 5.1. On May 29th, at 07:00 (UTC), another significant event of magnitude M L 5.8 occurred, located nearly 12 km W of the May 20th main event and close to San Felice sul Panàro. This event was followed by two aftershocks of M L P 5.0. The aftershocks of the May 29th events affected an area along the E–W direction, between the municipalities of Novi di Modena and San Fe- lice sul Panàro, for a distance of nearly 20 km. On June 3rd, a new event of magnitude M L 5.1, located to the W of the previous ones (Fig. 1) struck the same area. The maximum macroseismic intensity, measured on the European Macroseismic Scale (I EMS ), was VIII in the municipality of Cavezzo as the cumulative effect of the sequence [2]. In the most damaged municipalities (I EMS > VII), a few total collapses were observed. Collapses of individual buildings occurred in the municipalities of San Felice sul Panàro and Finale Emilia, as well as severe damage to monumental buildings and to old constructions [3]. 1350-6307/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.engfailanal.2013.02.009 ⇑ Corresponding author. Tel.: +39 06 4991 9166; fax: +39 06 322 1449. E-mail address: luigi.sorrentino@uniroma1.it (L. Sorrentino). Engineering Failure Analysis 34 (2013) 629–647 Contents lists available at SciVerse ScienceDirect Engineering Failure Analysis journal homepage: www.elsevier.com/locate/engfailanal