Degradation of historic masonry by analytical and digital photogrammetry: a quantitative analysis

The degradation of Cultural Heritage sites is one of the biggest challenges in modern societies and it is becoming a pressing issue in many countries. Our Cultural Heritage is degrading faster today than any time in the past. Countries as Italy, boast a significant part of the heritage buildings and structures all over the world, typically made of stone. These countries are increasingly challenged to properly maintain their important legacy while keeping maintenance low-costs for the preservation. The degradation of historic masonry structures can be manifested in different ways that can be focused from different perspectives and disciplines. The present study-case deals with the Ponari Nymphaeum, a Roman building dated to the 1st century B.C., that has been the object of a study begun in 2010. The site is located on the slopes of Montecassino, in the Southern Lazio and it has been the object of a survey and monitoring begun in 2010, and updated to 2019, aimed at documenting the structural and architectural degradation of the site due to the negligence and the climate change by using the combined approach of the analytical and digital photogrammetry.The results show the efficiency of the proposed methodology to identify not only the existing state of degradation of the site, but also a useful approach to preserve and to reconstruct the missing and damaged parts that can be reproducted with high accuracy.