Seismic assessment and retrofit of the Roman statues' installation at the Villa Oplontis site of the archaeological park of Pompeii

Villa Poppaea in Oplontis is a site part of the Archaeological Park of Pompeii, situated in the town of Torre Annunziata (Naples, Italy). In 2023, 15 Roman statues were installed at Poppaea’s Villa in Oplontis to set up an extended museum within the site, and enhance part of the statuary found there. These marble statues were installed on steel bases, with partial wooden cladding, placed close to the current path and in areas where the space and state of preservation and conservative characteristics were compatible with the museum's needs. The statues differ considerably in terms of size and volume, and the bases have different dimensions and heights but similar steel structures. This paper shows the feasibility study for the seismic retrofit of the collection of statues that respects the stringent preservation standards and the boundary conditions dictated by the special location of the statues. Firstly, a detailed on-site survey was carried out to assess the current configurations of the installation, with special attention devoted to elements that might be a source of interference. A preliminary seismic assessment was undertaken, highlighting that the most probable failure modes involve the overturning of the statues over their base and the eccentricity of the base that would cause second-order effects. A retrofit technique based on the application of Shape Memory Alloys (SMA) wires was therefore proposed. Finally, the retrofit design was validated by implementing the SMA elements using the FEM code OpenSees in STKO and performing non-linear time history analysis using sets of natural spectrum-compatible accelerograms. The results of the study underline the highly promising performance of the proposed technique in reducing the seismic risk of the statues, with a simple installation procedure and a minimally invasive solution.