Cultural Heritage: Anti-vibration technologies help preserve the Sarcophagus of the Spouses at National Etruscan Museum in Rome

An anti-vibration platform offering hich-tech protection from the effects of daily passing traffic and the threat of earthquakes to the "Sarcophagus of the Spouses", one of the greatest masterpieces of Etruscan art that have come down to us, which can be admired in the National Etruscan Museum of Villa Giulia in Rome. This is what a multidisciplinary team comprising ENEA experts, the company Somma engineering and Roma Tre and Sapienza universities is working at, as part of the project MONALISA (Active Monitoring and Isolation from vibrations and earthquakes of art objects), which has ranked first among the 81 participants in the LazioInnova tender funded by the Lazio Region [1].

To effectively protect the famous artwork, a series of infrastructures and technologies have been used including magnified motion, hi-tech sensors, 3D printing, vibrating tables, mechanical test benches, mathematical models and ENEAGrid computing resources for sharing -remotely and in real time- vibrating table experiments.

“History has taught us that earthquakes are the natural danger that poses major threats to our artistic and historical treasures. Seismic vulnerability assessment requires a thorough and detailed examination of the dynamic properties of the artwork and consequently of its position and seismic vulnerability. On the other hand, traffic-induced vibrations have a detrimental effect on our historic buildings and their contents, deteriorating them over time ", pointed out Paolo Clemente of the ENEA Laboratory for Analysis and Protection of Critical Infrastructures.

"In this context, the adoption of seismic isolation from seismic and traffic-induced vibrations, based on a significant reduction of dynamic loads at the base of the work rather than on its increased resistance, is an intelligent solution to avoid or at least limit damage, even in case of violent seismic events. This is why we hope that the MONALISA approach will become a methodological and technological model to adopt, when possible, to protect our country’s art treasures. ", Clemente said.

The Etruscan sarcophagus, with its protective showcase, will rest upon the innovative anti-vibration platform designed and built at ENEA, in collaboration with Somma, aimed at protecting the artifact both from earthquake shocks and daily traffic-induced vibrations, given the proximity of the Museum to the surface tramway and the underground section of the Rome-Viterbo railway.

"The daily stresses to which the Sarcophagus of the Spouses and the other works of art housed in the north wing of the Museum undergo, due to the vibrations coming from rail traffic, risk irremediably compromising their stability. The project MONALISA was awarded by Lazio Innova for its high impact in terms of scientific research, promotion of local businesses and safeguarding of the cultural heritage. We expect this alliance to lead to an innovative and advanced technology for preserving one of the most famous artifacts of Etruscan art, and hope researchers will provide us with a solution for all the remaining works exposed to these dangerous vibrations ”, said Valentino Nizzo, Director of the National Etruscan Museum of Villa Giulia.

"MONALISA is an industrial research and development project funded by the Region to increase companies’competitiveness on national and international markets in the field of Cultural Heritage. However, the technique can have broader applications, such as the protection of low-mass and high-value equipment. The project’s strenght lies in the diversified expertise and skills of its team and the collaboration of a company leader in anti-seismic devices design and production", said Luigi Sorrentino of  Sapienza University of Rome, technical-scientific coordinator of the project.

For the design of the vibration protection system, ENEA will also draw upon skills developed in prior studies, including seismic isolation of the Riace Bronzes and the statues of the Annunciation of the Orvieto Cathedral. The system will be validated on a copy of the "Sarcophagus of the Spouses" printed in 3D, through dynamic tests on the vibrating table of the Casaccia Research Center. The system consists in inserting devices with low stiffness in the horizontal direction in order to decouple the motion of the object to be protected from that of its base, which remains attached to the foundation or floor.

Photomodeling of the artwork, i.e. the creation of a 3D model using photographs,  will enable both to obtain mathematical models for the analysis of the vulnerability to vibrations induced by traffic and earthquake and to create a 3D copy. The photomodeling procedure will also be integrated with the vulnerability assessment of the different types of objects exhibited in the Museum, conducted by Roma Tre University.

ENEA will also design a monitoring system based on fiber optic sensors, with minimum encumbrance and  maximum versatility, which measures resonance and amplitude of vibrations of the foundation, the insulation system and the art piece, also generating an alert signal when a pre-established risk threshold is exceeded.

Furthermore, in order to "measure" the energy transmitted to the artwork by vibrations and obtain essential indications to design the isolation and monitoring systems, the ENEA experts will use both conventional sensors (velocimetric and accelerometric), and the magnified motion technique [2] -already widespread in the medical and security fields- capable of measuring and showing the movements of structures and objects, and which the ENEA researchers were the first in the world to use on cultural heritage.

Basically, through the analysis of pre-recorded videos, the magnified motion amplifies the small movements of the object, making them visible and allowing to identify the most vulnerable parts, at risk of breakage or collapse, and therefore to intervene preventively to protect the object from future seismic or traffic-induced vibrations. The same system can be used to identify the parts of a fresco that are more degraded or subject to detachment.

After the installation of the isolation device, ENEA will perform new measurements of environmental and traffic-induced vibrations to test, in real operating conditions, the protection and monitoring systems and the analysis and engineering interpretation of the experimental data obtained, both in situ and on a vibrating table.

Found in 1881 in 400 fragments during the excavations in the Banditaccia necropolis in Cerveteri (Rome), the Sarcophagus of the Spouses is 1.4 meters high and 2 meters long and depicts a couple of semi-reclining spouses, in a position of equal status, showing that Etruscan culture considered women as equals of their male counterparts in terms of rights and dignity. Despite its name, it is actually a funeral urn of polychrome terracotta made in the sixth century BC.

• Valentino Nizzo (Director National Etruscan Museum of Villa Giulia, Rome)
• Luigi Sorrentino (Sapienza University of Rome)
• Maria Aurora Vincenti (ENEA)
• Miriam Lamonaca e Maria Paola Guidobaldi (National Etruscan Museum of Villa Giulia, Rome)

Maria Aurora Vincenti, ENEA – Laboratory of Micro and Nano Structures for Photonics, 

Paolo Clemente, ENEA – Analyses and Protection of Critical Infrastructures Laboratory, 

Ivan Roselli, ENEA – Laboratory of Technologies for the Dynamics of Structures and Seismic and Hydrogeological Risk Prevention

Vincenzo Fioriti, ENEA – Laboratory of Technologies for the Dynamics of Structures and Seismic and Hydrogeological Risk Prevention

Michele Arturo Caponero, ENEA – Laboratory of Micro and Nano Structures for Photonics

[1] Framework program agreement "Research, Technological Innovation, Telematic Networks" [1] (APQ6) – Excerpt "Implementation of programmatic interventions and new interventions relating to the Technological District for new technologies applied to cultural assets and activities". Intervention TE1 - Invitation to the Center of Excellence to present projects for the second phase - CSR Projects (Det. G07413 of 16.06.2021, published in BURL n. 61 of 22.06.2021, Act of Commitment of 18.10.2021).

[2] Optoelectronic motion capture system for measuring displacements in a dynamic field, high-speed video instrumentation for magnified motion