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Two 5.9 M w and 5.8 M w earthquakes hit Emilia-Romagna region on May 2012. Most of the precast RC one-story structures exhibited significant damage, causing huge economic losses as well as deaths. These events produced in-situ observations and data to develop a deeper knowledge on the seismic behavior and collapse of this structural typology. This paper deals with the seismic assessment of a real precast RC industrial building with friction connections. The structure is located in Emilia-Romagna region and it was severely damaged during the second seismic event on May 29th. Structural columns exhibited cracking and yielding at the base as well as significant rotations along one direction. Moreover, relative displacements were recorded in both beam-to-column connections and roof-to-beam connections and several loss of support phenomena occurred for the roof elements. A detailed nonlinear structural model is defined in OpenSees code and nonlinear dynamic analyses are performed with the recorded accelerations time-histories of the two seismic events. By comparing the numerical results with the actual response of the structure, the adopted model is validated and the main damage typologies are also justified. [ABSTRACT FROM AUTHOR]

An earthquake sequence struck the province of L'Aquila (central Italy) leaving 305 dead, about 1,500 injured, and 29,000 homeless. Hundreds of low-intensity events occurred between January and March, 2009. The mainshock took place on April 6, 2009, and its epicenter was located at about 6 km southwest of L'Aquila town; three stronger aftershocks happened on April 7 and 9, 2009. This paper focuses on actual performance of older and more recently constructed building structures during the earthquake sequence. After the main seismological characteristics of the sequence are described, the most significant observed damages are analyzed and associated with theoretical failure modes for both reinforced concrete and unreinforced masonry buildings. Since older masonry structures were more seriously damaged, the effects of the earthquake are described with more emphasis to ordinary masonry and cultural heritage buildings (churches, palaces, and castles). In conclusion, a number of lessons may be learned from the L'Aquila earthquake sequence. Several features are highlighted and some proposals are given to upgrade the current methods of structural analysis, as well as the existing codes. [ABSTRACT FROM AUTHOR]