The Dynamic Monitoring of the Temple of Neptune in Paestum

The knowledge of the health state and its evolution over time is fundamental for the development of maintenance processes aimed to protect and preserve the monumental architectures. In complex conditions, characterized by natural hazards and climate-change, the knowledge of the static and dynamic behaviour of the structures can be achieved using monitoring systems by means of innovative devices and real-time analysis procedures. In this context, thanks a joint project of applied research between the Department of Civil Engineering of the University of Salerno and the Archaeological Park of Paestum & Velia, a dynamic monitoring network was installed on the Temple of Neptune in Paestum (Southern Italy).  

The monitoring network consists of mechanical and electronic components of high sensitivity and robustness, based on the innovative “UNISA Folded Pendulum” seismometers [1]. The network, which is implemented as an intranet, is an open system and expandable with any type of analog sensor. The seismometers are connected through DAQ (National Instruments – FieldDAQTM) to an Intranet to monitor globally and locally the response of the main structural elements. The monitoring network is composed of 14 measuring: 3 points on the foundation plan, 8 points on the entablature and 3 on the stylobate. The measuring points differ in two configurations: 8 biaxial (red points in the figure) and 6 triaxial (blue points in the figure). The underground devices are placed in concrete wells to ensure cleanliness and maintenance accessibility; the sensors on the entablature of the temple are placed into plexiglass boxes for protection from atmospheric agents and birds; the sensors on the stylobate are non-fixed in order not to interfere with the fruition of the temple.

The sensors are connected to the network by means of National Instruments FieldDAQTM, which has the following main characteristics: supported sensors ±10V Analog Input, sample rate (simultaneous) up to 102.4 kSample/s/ch and protection rating IP67. The seismometers’ data are acquired by means of a control unit installed in the National Archaeological Museum of Paestum thanks to a fiber optical link. This way, it is possible to perform the synchronous signal acquisition at 24 bit with a sampling rate of 2084 Hz.

This type of network enables the acquisition of seismometric signals, which provide fundamental information about the behaviour of the temple and its evolution over time. This information is used to prevent and identify potential problems and to plan proactive maintenance.

This project has been made possible thanks to the generous financial support of local private companies through Artbonus. Moreover, the project allowed for public access to real-time data visualisation of the Temple via a dedicated page on the website of the Archaeological Park of Paestum and Velia [2].

REFERENCES

1. Barone F and Giordano G, 2018, The UNISA Folded Pendulum: A very versatile class of low frequency high sensitive sensors, Measurement, Elsevier, Amsterdam, vol. 118 p. 339-347, doi: https://doi.org/10.1016/j.measurement.2017.09.001;

2. Sesimic monitoring of the Temple of Neptune – Ongoing Activities: https://museopaestum.cultura.gov.it/monitoraggio-sismico-del-tempio-di-nettuno/