High resolution operational modal analysis of Sant'Agata del Mugello in light of its building history. (1st March 2022)

• Record Type: Journal Article
• Authors: Montabert, Arnaud; Mercerat, E. Diego; Clément, Julien; Langlaude, Philippe; Lyon-Caen, Hélène; Lancieri, Maria
• Is Part Of: Engineering structures. Volume 254(2022)
• Publication Date: 2022-03-01
• Subjects: Operational modal analysis -- Enhanced frequency domain decomposition -- Natural frequency -- Mode shape -- Damping ratio -- Medieval church -- Masonry -- Sensor placement; Structural engineering -- Periodicals; Structural analysis (Engineering) -- Periodicals; Construction, Technique de la -- Périodiques; Génie parasismique -- Périodiques; Pression du vent -- Périodiques; Earthquake engineering; Structural engineering; Wind-pressure; Periodicals; 624.105
• DOI: 10.1016/j.engstruct.2021.113767
• Languages: English
• ISSNs: 0141-0296

Abstract

Abstract: The building history of a cultural heritage building and the after-effects induced by extreme loads such as earthquakes have a durable impact on its modal parameters. This article aims to discuss the peculiarities of some modal parameters extracted from ambient vibration measurements in light of the complex history of Sant'Agata del Mugello. The Romanesque church located in the Mugello basin (Tuscany, Italy) suffered from many earthquakes, at least from 1542. In this context, we carried out two dense ambient vibration campaigns in March and June 2019. We extracted each mode's natural frequency, mode shape, and damping using the Enhanced Frequency Domain Decomposition. We identified ten modes. Some modes highlight structural singularities related to the building history of the church: rocking of the base of the bell tower; phase opposition between the bell tower and the nave; bending of the walls of the nave. Since the instrumentation benefited from a vast number of recording positions (83), we tested the impact of the sensor placement strategy on the resolution of the identified modal parameters in the specific case of Sant'Agata del Mugello. The resolution of the higher-order modes decreases strongly in case of degraded sensor placement strategy impacting the dynamic analysis of the church. Highlights: We performed two in situ campaigns to estimate the modal parameters of the Sant'Agata del Mugello church. We highlight the impact of the building history and after-effects of historical earthquakes on modal parameters. We highlight the impact of the sensor placement strategy on modal parameters.