A Simplified Procedure for the Out-of-Plane Seismic Assessment of Free-Standing URM Elements: Application to the Abandoned Ancient Village of Bussana (Sanremo, Imperia - Italy)

Abstract

ABSTRACT This paper addresses the safety of connections within urban areas, where free-standing elements that menacingly overlook them are susceptible to potential overturning mechanisms. Such a condition recurs in post-earthquake scenarios and in historical centers abandoned after disasters in seismic-prone areas, which aimed to be restored to create safe pathways for tourists. The paper presents a simplified procedure for the out-of-plane seismic risk assessment of free-standing unreinforced masonry (URM) elements in historical centers. The procedure can be applied to several URM free-standing elements, such as artistic pieces or nonstructural components, but also rocking panels resulting from the collapse of structures in post-event damage scenarios. The procedure is based on the definition of hazard, exposure, and vulnerability, which are combined to assign a risk class to each element and define a priority of intervention. The procedure relies on the kinematic approach but requires a limited number of parameters to be feasible when applied to many elements. Some of them can also be acquired through innovative survey techniques, like unmanned aerial vehicle photogrammetry. To demonstrate its utility, the procedure is applied to the abandoned village of Bussana (Sanremo, Imperia — Italy), severely hit by the 1887 earthquake and partially reoccupied in the 1960s.