Evaluation of static and dynamic long-term structural monitoring for monumental masonry structure

This paper presents the comparative results of the static and dynamic monitoring of damaged masonry macro-elements. The structural health monitoring (SHM) has been carried out over 3 years. The crack opening displacement of the main shear cracks of the overturning mechanisms of the façade, of the bottom walls of transept and the cracks of the arches was monitored using extensometers. Moreover, dynamic sensors for measuring accelerations were used and through the registration of each major seismic vibration event, a modal identification of output-only systems was carried out; the main frequencies were identified. This work highlights the structural damage detection methodology and shows the differences between global and local damage detection techniques. The static monitoring presents the displacement trend of each monitored main crack with its respective temperature–time history. The results of both long-term monitoring systems are compared to develop the reliability and the correlation of the static and dynamic parameters over 3 years. Static and dynamic monitoring are useful to check both the level of damage and the degradation of the cracking survey, to evaluate the interaction with the safety measures, and also to analyze the stability of signals by varying the intrinsic and environmental conditions such as temperature. This research reveals a good reliability between the static and dynamic results, particularly on the detection of the effect of a safety intervention. Moreover, the results highlight the limits and merits of each monitoring system.