Seismic vulnerability of ancient churches. Part 1: damage assessment and emergency planning

This paper describes the new methodology used to assess seismic damage in the churches of Umbria and the Marches, which is based on 18 indicators, each representative of a possible collapse mechanism for a macroelement. The subdivision of the church into macroelements consists of the identification of architectonic elements in which the seismic behaviour is almost independent from the rest of the structure (facade, apse, dome, bell tower etc.). For each macroelement, by considering its typology and connection to the rest of the church, it is possible to identify the damage modes and the collapse mechanisms. During inspections operations, the surveyors must indicate: a) the actual macroelements; b) the damage level c) the vulnerability of the church to that mechanism, related to some specific details of construction. From these data a damage score i defined, which is a number from 0 to 1 obtained as a normalised mean of the damage grades in each mechanism. The analysis of the collected data (more then 1000 churches in Umbria) allows the definition of the correlation between macroseismic intensity and damage.