MS22.5 - Vibration-Based Assessment and SHM of Cultural Heritage Structure

Control charts have become a common method for damage detection within vibration-based structural health monitoring. Successful applications have been implemented including for historical buildings preservation. Nonetheless, their performance is affected by several algorithm parameters that should be properly set and more research is needed to optimise such tools. To this end, the present work discusses the preliminary results of a project that focuses on the development of a cost-effective damage detection strategy based on control charts for masonry towers in seismic-prone areas. Here, a prototype of a historic tower is defined based on an extensive documentary search, a methodology to simulate realistic long-term monitoring data is developed and, finally, different parameters that may affect the damage detection performance are analysed and compared against small-extent damage scenarios. The importance of normalising the features to account for seasonal fluctuations and setting a correct threshold for detection clearly emerged and drives the future scope of the work.

In this paper, the results of over two years of continuous monitoring of the twin bell towers of the Cathedral of Camerino (Italy) are presented. The monitoring activity target is the evaluation of the dynamic behavior of the twin belfries after the damages occurred during the seismic events of 2016 and the application of fast securing. The experimental data are acquired in continuous using four triaxial MEMS accelerometers, two for each structure, on two opposite corners of the bell cells. Data processing is managed with an automatic system which elaborates the signals and executes Operational Modal Analysis to track the modal characteristics of the structures and their evolution in time. Correlation with environmental factors allows to discern the effect of climatic conditions on the variations of dynamics.