Dynamic Monitoring of a Large Historical Masonry Building: The Ex-Ciechi Institute in Florence, Italy

Dynamic monitoring is widely recognized as an effective and noninvasive tool for acquiring essential information on the dynamic behaviour of structures and for supporting seismic safety assessment. This study focuses on the former Istituto dei Ciechi in Florence, a large three-story masonry building with one partially underground level, covering an area of approximately 4000 m 2 on a plot of 10,381 m 2 . The building is composed of four symmetrically positioned and interconnected blocks. The complex, erected in 1928, was enlarged in 1936 through the addition of a second floor. This modification required foundation reinforcement and changes in wall typology between the newly raised section and the original structure. Given the large size of the structure and its geometric complexity, the building was monitored block by block, using a total of 12 triaxial velocimeters for each block. Three additional sensors were installed at the basement and maintained as reference sites throughout the entire monitoring period. Measurements were also conducted on the surrounding soil to evaluate its dynamic characteristics and possible soil-structure interaction effects. Data analysis, performed both in time and frequency domains, enabled the identification of the main modal frequencies and highlighted differences in dynamic response between the monitored sectors. The experimental results obtained from both the structure and the soil provide significant constraints for the numerical modelling and structural analysis phases, allowing the estimation of the building’s dynamic response and the identification of potential structural vulnerabilities.