On the seismic risk of medieval Italian masonry towers

The paper, after a brief discussion of the methodologies of the research project RiSEM (Seismic Risk of Monumental Buildings), a research project started in 2011 and concluded at the end of 2013, discusses on the seismic assessment of historic masonry towers according to the Italian "Guidelines for the assessment and mitigation of the seismic risk of the cultural heritage". The RiSEM project aimed at developing and testing innovative and expeditious methodologies (i.e. without direct contact with the masonry building) to evaluate all the main structural features of the monumental buildings that are required for the assessment of their seismic safety. As a relevant case study the historic towers of the city of San Gimignano (Italy) in the UNESCO list of the World Cultural Heritage was selected, and the paper summarizes the analyses and the results obtained on three of the analysed towers. The Italian Guidelines identify a methodology of analysis based on three different levels of evaluation, according to an increasing path of knowledge (or requirement) of the structure, namely: LV1 (analysis at territorial level), LV2 (local analysis) and LV3 (global analysis). The paper, summarizing the results obtained for two of the above three levels, highlights a few issue concerning the seismic risk of historic masonry tower.