Urban-Scale Dynamic Screening for the Preliminary Seismic-Risk Prioritization of Masonry Buildings

Abstract

This paper proposes an urban-scale dynamic screening method for the preliminary seismic-risk prioritization of masonry buildings. The method is based on the integration of rapid surveys, relational databases, geographic information systems, and accelerometric data recorded during seismic events. It is not intended to replace comprehensive seismic vulnerability or risk assessment procedures. In its present formulation, it provides an event-specific preliminary dynamic-priority indicator, derived from recorded ground motions, to support post-event inspections and subsequent detailed analyses at the urban scale. The procedure combines a rapid visual survey (on average covering ca. 300 buildings per day) with a database management system (DBMS) linked to a three-dimensional cartographic database of the building stock. The geometric and structural information collected in the field is integrated with the processing of ground acceleration records, from which the pseudo-acceleration spectra, peak ground acceleration (PGA), and spectral amplification ratios (DAF) are derived. Through the relationship between spectral period and building height, the method identifies height classes and number of storeys corresponding to the highest spectral amplification ratios derived from the recorded ground motions. Buildings belonging to these classes are not classified as vulnerable in absolute terms, but are considered priority buildings for subsequent checks, inspections, or detailed analyses. The method was applied to the municipalities of Umbertide and Gubbio, in the province of Perugia, which were affected by the seismic sequence of 9 March 2023. The processed accelerometric records identified Classes I, II and III, corresponding to one-, two-, and three-storey masonry buildings. The illustrative GIS application focused on Classes II and III; 27 of the 33 masonry buildings included in the damaged-building sample (82%) belonged to these two classes. The main contribution of the study is the definition of an integrated, rapid, and replicable workflow that can support local authorities, technicians, and civil protection operators in the preliminary management of seismic risk at the urban scale.