Procedures and experiences in the post-earthquake usability evaluation of ordinary buildings

One of the most critical issues in the post-earthquake emergency is assessing the usability of buildings in order to restart as soon as possible all the activities in the stricken area while permitting people to go back as safe as possible to their houses. Generally, this is made by means of surveys based on usability forms to be filled out by expert technicians. Different countries adopt different forms whose result in terms of usability is dependent essentially on building damage. The Italian approach accounts for, beyond the damage state, also the vulnerability of the building under examination. In this study, the data collected through the widespread survey performed in the aftermath of the L’Aquila (Italy) 2009 earthquake has been analysed, showing that some buildings judged as not usable although having null or very low damage. Therefore, the role of other causes, among which vulnerability, determining the negative usability outcome has been discussed out. Finally, a practical case faced by the authors during the usability survey in Emilia (Italy) after the 2012 seismic sequence highlights the role of vulnerability on the usability outcome.