PSI - Issue 44

Caprino Amedeo et al. / Procedia Structural Integrity 44 (2023) 1578–1585 A. Caprino et al./ Structural Integrity Procedia 00 (2022) 000 – 000

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1. Introduction In the last decade, remote sensing methods have risen in support of traditional techniques for structural health monitoring (SHM). Synthetic Aperture Radar Interferometry (InSAR) for processing satellite images allows to retrieve periodic, non-invasive and widespread data, that may be employed for detecting structural problems and vulnerabilities at both urban and local scale. Moreover, thanks to the increasing millimetre-scale accuracy, Multi Temporal InSAR methods (MT-InSAR), such as PSInSAR (Ferretti et al., 2001), have become a powerful tool for the analysis of deformations of infrastructures (Macchiarulo et al., 2022; Sartorelli et al., 2021; Selvakumaran et al., 2018), buildings (Xiong et al., 2021; Zhu et al., 2018) and historical structures (Cavalagli et al., 2019; Cigna et al., 2014), aiming at detecting coherent measurement points that provide the displacements velocity along the line of sight (LOS) and deformational time series. The research on the field is rapidly progressing, however some issues are still to be addressed (Lenticchia et al., 2021). In this contribution, an application of MT-InSAR to a case study is presented. Satellite images acquired by the COSMO-SkyMed, for both ascending and descending orbits, referred to the centre of Padova were processed through PS-InSAR to identify Measurement Points (MP). Later, the attention was focused on the case-study, the Scrovegni Chapel and its surrounding area. The analysis of interferometric data was carried out, focusing on the deformation rate detected by the satellite along the LOS and along both vertical and horizontal directions, combining the two different orbits. Last, possible correlation between displacement time series and environmental parameters (temperature and humidity) was analysed. For this purpose, two sources of environmental data were considered: data provided from two in situ sensors installed on the structure and data provided by a local meteorological station located about 2.5 km far from the Chapel. 2. Material and methods 2.1. Case study The Scrovegni Chapel is a XIV century small church located in the city centre of Padova (Fig. 1). The Chapel rises next to the site of the Roman Arena and to the complex of former Eremitani Monastery, which nowadays hosts the Museo Civico of Padova. The church has recently become a UNESCO site and it is worldwide famous for its frescos, which run all over the interior surfaces both on walls and on intrados of vaults, painted by Italian artist Giotto. Due to its importance, the Chapel is constantly controlled by a monitoring system installed in 2013 and consisting of a mixed of static, dynamic and environmental sensors.

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Fig. 1. (a) Main façade of Scrovegni Chapel; (b) city centre of Padova planimetry (the red dot indicates the location of the Chapel)

2.2. Methodology

The analysis of the Scrovegni Chapel is performed into three different steps, such as: • Application of PSInSAR interferometric process;