Subsidence Monitoring in the Duomo di Milano: Half a Century of Measuring Activities

Constant monitoring activities of vertical settlement in the Duomo di Milano started during the ’60 when the rapid changes of the water table seriously affected the stability of the Cathedral. This paper describes the origin and evolution of the monitoring system, which is still operative thanks to continuous maintenance and technological advancements in measurement and processing methods. Nowadays, measurements are still acquired twice a year as a part of the traditional monitoring work, which is based on several other systems, including automatic and manual (mechanical) sensors and tools. A digital archive with more than 50 years of data is constantly updated, continuing a tradition that followed major restoration interventions and ordinary maintenance carried out by Veneranda Fabrica del Duomo di Milano (VFD). After more than half a century, the collaboration between VFD and Politecnico di Milano to monitor the Duomo is still active.