PSI - Issue 64

Alex Carpenter et al. / Procedia Structural Integrity 64 (2024) 319–326 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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paper discusses the implementation of SHM systems in historic places of faith. Section 2 provides a review of sensors implemented in 45 sites. Criteria for consideration in the review consists of peer-reviewed articles obtained from engineering databases that detail sensor usage in pre-1924 buildings constructed as places of worship. The case study of the Cathedral of the Immaculate Conception is used to contextualise this review in Section 3 , detailing the current state of the building, sensor selection, and staging and timing of sensor implementation. 2. Sensor usage in historic places of faith This review briefly analyses the effectiveness of sensors discussed in 45 academic articles that detail SHM implementation in 45 historic places of faith. Case study requirements for consideration include structures built as places of worship before 1924. Table 1 details the types of sensors implemented and their benefits, limitations, and noted uses as well as the location of the host structure. The buildings monitored are primarily stone or brick masonry, excepting the timber structures of Frankfort Church in Dallas, Texas, U.S.A. (Samuels, et al., 2011) and an un-named 14 th century church in Domachowo, Poland (Pawlak, et al., 2023), as well as the adobe-walled San Pedro Apostol de Andahuaylilas Church (Aguilar, et al., 2019) (Zonno, et al., 2018). In addition to favouring masonry structures, the list involves a bias towards European conservation standards and practices, with only 12 of the 45 sites from outside the continent (Samuels, et al., 2011) (Aguilar, et al., 2019) (Zonno, et al., 2018) (Sánchez, et al., 2016) (Kosnik, et al., 2013) (Salvatore & Eleonora, 2020) (De Ponti, et al., 2017) (Takhirov, et al., 2023) (Yanik, et al., 2023). This bias extends towards conservation of Christian structures, exempting 5 mosques and 2 Hindu temples (Nguyen & Livaoğlu, 2023) (Takhirov, et al., 2023) (Yanik, et al., 2023). The reason for monitoring plays a vital role in the sensor selection process. The analysed articles featured sensors used in long-term SHM systems and short-term monitoring (duration of less than a year), including ambient vibration testing (AVT) and damage analysis following recent seismic activity. Seismic risks were a prominent consideration in the SHM systems reviewed, specifically mentioned for 29 of the case studies in Table 1. Sites in earthquake-prone areas receive a greater benefit from AVT, as the frequencies measured can be analysed to determine the structural stability during seismic events. As such, buildings in locations with seismic activity will make a greater use of seismometers and velocimeters, potentially foregoing environmental sensors when performing AVT. Long-term SHM systems are more likely to utilise sensors monitoring displacement, tilt, stress, strain, loading, temperature, humidity, and wind speed. Table 1 lists crack metres, extensometers, and linear variable differential transformers (LVDT) (all of which measure the displacement between two anchored points often, but not necessarily, across a crack) where specified. Accelerometers are noted to be beneficial for both long-term monitoring of structural deterioration and short-term monitoring for seismic concerns. Table 1. SHM sensor use in peer-reviewed articles on the monitoring of historic places of faith (Abbati, et al., 2023) (Ackigoz, et al., 2022) (Aguilar, et al., 2019) (Baggio, et al., 2021) (Bednarski, et al., 2017) (Bianconi, et al., 2020) (Blanco, et al., 2019) (Boscato, et al., 2016) (Boscato, et al., 2013) (Calcina, et al., 2013) (Ceravolo, et al., 2021) (Ceravolo, et al., 2017) (Chrysostomou, et al., 2004) (Colla & Pascale, 2014) (De Ponti, et al., 2017) (Di Lorenzo, et al., 2019) (Elyamani, et al., 2016) (Gentile, et al., 2019) (Karanikoloudis, et al., 2021) (Kita, et al., 2021) (Kosnik, et al., 2013) (Lima, et al., 2008) (Lombillo, et al., 2015) (Lorenzoni, et al., 2016) (Makoond, et al., 2022) (Makoond, et al., 2020) (Marazzi, et al., 2011) (Masciotta, et al., 2017) (Mesquita, et al., 2018) (Nguyen & Livaoğlu, 2023) (Pawlak, et al., 2023) (Perez-Gracia, et al., 2019) (Potenza, et al., 2015) (Ramos, et al., 2010) (Russo, 2012) (Saisi, et al., 2018) (Salvatore & Eleonora, 2020) (Samuels, et al., 2011) (Spoldi, et al., 2021) (Sánchez, et al., 2016) (Takhirov, et al., 2023) (Vincente, et al., 2023) (Yanik, et al., 2023) (Zonno, et al., 2018) Sensor Benefits Limitations Building

Reasoning for sensor use (# of case studies)

location (# of case studies) Italy (2) Portugal (1)

Seismometer (Di Lorenzo, et al., 2019) (Gentile, et al., 2019) (Karanikoloudis, et al., 2021)

- Provide local and global response of structure - Minimal sensitivity to environmental changes - Small

- Limited to use for seismic monitoring - Less beneficial for long-term monitoring - Large & bulky - Less user-friendly than accelerometers

- Ambient vibration testing (2) - Monitoring seismic impacts (1) - Ambient vibration testing (5)

Velocimeter (Abbati, et al., 2023) (Karanikoloudis, et al., 2021) (Salvatore & Eleonora, 2020) (Spoldi, et al., 2021) (Takhirov, et al., 2023)

- Effective for AVT measurements

Italy (2) Nepal (2) Uzbekistan (1)