SMA materials for the seismic protection of Roman age statues at the Oplontis site of the Archaeological Park of Pompeii

In 2023, 15 Roman marble statues were installed at Villa Poppaea in Oplontis (Torre Annunziata, Naples, Italy), part of the Archaeological Park of Pompeii, to expand the on-site museum and enhance the display of local heritage. The statues, mounted on steel bases with partial timber cladding, vary significantly in geometry and mass distribution, introducing challenges in seismic safety assessment due to their slenderness and elevated centres of gravity. This study presents a seismic retrofit strategy aimed at reducing the vulnerability of these artefacts while adhering to strict conservation constraints and the architectural integrity of the site. A detailed on-site survey was conducted to document the installation conditions, with particular focus on base eccentricities, support flexibility, and potential interaction with surrounding elements. A preliminary seismic vulnerability assessment identified predominant failure mechanisms, particularly rigid-body rocking and overturning, intensified by collision risks and base eccentricity-induced P-Δ effects. To mitigate these risks, a retrofit solution employing Shape Memory Alloy (SMA) wires was proposed, exploiting their recentring capability and energy dissipation with minimal visual and structural intrusion. Numerical simulations were carried out using OpenSees within the STKO platform. Nonlinear time history analyses were performed using natural spectrum-compatible accelerograms representative of local seismicity. Results demonstrate that the SMA-based intervention effectively reduces displacement demands and prevents overturning, offering a low-impact seismic mitigation strategy for freestanding heritage objects.