Importance of Monitoring,Behavior Analysis,and Diagnostic Techniques for Preservation of Great Historical Structures

A synthetic overview is presented of the motivations, technological possibilities, and benefits of the practice of providing large structures with monitoring installation and interpretative activities. Starting from the large body of experience gained in the field of dam engineering, the gradual penetration of these techniques in the area of preservation of monumental building is surveyed. Particular attention is dedicated to the case of the Brunelleschi Cupola in the Florentine Cathedral of Santa Maria del Fiore. The more pressing needs for the next-future development of these studies and practices are then enunciated, with the auspice that the obstacle posed to their diffusion by the difficulty of collecting adequate financial funds may be overcome in the best interest of the conservation of a precious historical-cultural heritage.     

Santa Maria del Fiore Dome Behavior: Statistical Models for Monitoring Stability

The article describes the work in progress for analysis of the behavior of the web cracks on Brunelleschi’s Dome of Santa Maria del Fiore. The web cracks in the Dome have always given rise to concern about the stability of the monument. The analyses performed show a slight increase in the size of the main cracks and, at the same time, a relationship with the environmental variables. None of the studies conducted in the past simultaneously involved all the variables detected by the monitoring system. Understanding the relationships among all the endogenous and exogenous variables characterizing the phenomenon under study can help to predict the static evolution of the monument and to automatically detect any atypical behavior, the identification of which would, of course, be of paramount importance for the preservation of the monument, and, more in general, for the preservation of the cultural heritage.     

Dome of the Basilica of Santa Maria Degli Angeli in Assisi: Static and Dynamic Assessment

This study presents the results of the static and dynamic assessment of the dome of the Basilica of Santa Maria degli Angeli in Assisi, designed by Galeazzo Alessi. The first section is devoted to an overview of the masonry domes designed by the Italian architect and focuses on the structural solutions adopted in the several cases described to better understand Alessi’s designing skills. In the second part, the drum-dome system is analyzed in order to attain a structural assessment. The static assessment is performed by means of limit analysis and finite element model approaches with non-linear mechanical behavior. The obtained results are consistent with the detected crack pattern and confirm the suitability of the reinforcement steel rings applied to the drum. The seismic assessment has been performed by response spectrum analysis. Due to the lack of specific information, a probabilistic approach for the material mechanical properties was used. The results obtained highlight an adequate seismic response of the structure that can be attributed to the dynamic properties of the slender drum-dome system. This finding justifies the good performance of the structure during the seismic events of 1832 and 1997.     

An Automatic Modal Identification Procedure for the Permanent Dynamic Monitoring of the Sanctuary of Vicoforte

ABSTRACT

The interest in automatic modal parameter extraction techniques has increased significantly in recent years because of the rising demand for Continuous Structural Health Monitoring (CSHM) of civil structures and infrastructures. The wider use of CSHM is related to its capability for early damage detection and therefore to its usefulness for planning maintenance and strengthening interventions. This article presents the main steps followed in creating a robust routine to run on an online basis the first-ever Continuous Vibration-Based Structural Health Monitoring (CVB-SHM) of a large masonry oval dome, i.e., the dome of the Regina Montis Regalis Basilica, also known as Sanctuary of Vicoforte. The procedure uses an output-only stochastic subspace identification method complemented by an automatic analysis applied to identification results, which are typically provided in terms of stabilization diagrams. In this study, the fully automatic procedure also includes a hierarchical clustering algorithm to separate authentic from spurious modes.