Assessment and analysis of damage in L'Aquila historic city centre after 6th April 2009

The paper describes the output of a survey carried out in the district of L'Aquila, Italy, in May 2009 after the April earthquake and later in January 2010, and the consequent vulnerability assessment completed by the authors. Observations collected on site regard masonry buildings of the historic centre of L'Aquila and the towns of Paganica and Onna; particular focus was given to a number of buildings of interest, which better represent two locally recurrent building typologies: the mansion and the common dwelling. A description of the main structural features and their influence on damage mechanism is provided, stressing the importance of elements such as wall lay-out, quality of masonry and strengthening interventions. The gathered information is used as input for the application of the FaMIVE method (D'Ayala and Speranza in Earthq Spectra 19(3):479-509, 2003), whereby feasible collapse mechanisms and the associate failure load factors can be identified. The procedure is briefly outlined and results are discussed from the point of view of the performance point: push-over curves produced by statistical elaboration of FaMIVE's output are compared both with the demand spectra obtained from EC8 and the response spectrum for the main shock as recorded by the closest station to the town. Conclusions are drawn on the reliability of the FaMIVE method with respect to its capability of predicting the damage mechanism identified on site.