The collapse of the "Casa dello Studente" during the 2009 earthquake in L'Aquila

The building hosting an University dorm and named “Casa dello Studente” was erected between 1965 and 1967 for a mixed use (residential/commercial). The plan of the residential part, in the upper four stories, was subdivided in three wings, connected through the stairwell. Ground story and a first basement were common to all the wings; a second underground level was below the South wing only. In 1979 the building was bought by an University Institution to be used as a student house. A wide refurbishment intervention, not covering the structural system, was performed during the years 1999-2005. During the April 6, 2009 earthquake of L’Aquila a partial collapse took place, limited to the North wing. Two distinct collapse zones were detected in the wing: the failure of all the columns at the ground floor, with a soft/weak story mechanism, and that of three columns along the height of the building. It was thus necessary both to explain the collapse sequence and to determine its causes. The factors possibly leading to the failure have been examined with a multidisciplinary approach: studies were extended to the concrete properties, to the ground motion experienced at site and to the dynamic behavior of the building in both the original and the final configuration.