The design of works in archaeological areas necessitate a methodological approach that considers advanced knowledge of materials, construction details, and structural degradation that influence the global behaviour of the heritage asset. However, it is often not possible to obtain a complete and exhaustive knowledge during the design phase; in particular excavation activities can reveal ancient structures that may be affected by particular static and seismic vulnerabilities, which may lead to local interventions that should be of minimal impact yet effective for the safety of the asset.

In adherence to the principle of minimum intervention and maximum reversibility, the design approach for consolidating archaeological structures  could be almost "tailor-made",  highly targeted and effective, seeking solutions that are simultaneously minimally invasive yet innovative.

In order to propose best practices that can serve as a guide, since no specific code seismic regulations  is now available within the archaeological field , this case will give an overview   of the design approach that is needed.

A case study is presented: the Insula Meridionalis in Pompeii. The restoration project for the Insula Meridionalis in Pompeii comprises a series of local interventions deemed necessary to guarantee the static and seismic safety of this vast architectural and urban complex. Enhancement is achieved through structural and architectural interventions that do not alter the historical value of the artefact but strike a proper balance between safety, protection, conservation.

The settlement of Pompeii, located in Regio VIII approximately 30-40 metres above the alluvial valley of the Sarno River, with its extensive aggregate of buildings, represents a true vertical stratigraphy telling us the site's history. The Insula Meridionalis extends in a double curvature for over 450 metres, initially from Villa Imperiale to the Baths of Sarno, then the second section from the House of Aelius Magno to the House of Giuseppe II and the Triangular Forum. The settlement provides clear evidence of the construction techniques employed during the Roman era, overlaid with recent restoration interventions that have utilised cement and metallic reinforcements. The complexity of the system, encompassing architectural and landscape elements, as well as geological, archaeological, and intangible components, makes the safeguarding and restoration of ancient structures particularly challenging. This task includes the 'de-restoration' of modern reinforced concrete structures that have deteriorated over time, the application of technologies derived from various scientific fields, and even vegetational restoration techniques. All these works require in-depth knowledge, beginning with surveying, diagnostic investigations, and ongoing monitoring during the works, aimed at identifying areas at risk of collapse and heritage degradation.

The study of the crack pattern is fundamental for understanding the various actions that have affected the archaeological structures: ancient and recent earthquakes, volcanic eruptions, subsidence, bombardments, and deterioration due to lack of maintenance. This knowledge is essential for selecting the appropriate intervention to protect such a complex heritage.

A critical analysis of the intervention results  will highlight the effectiveness of the conceptual methodological approach for addressing this complex urban settlement with targeted solutions that necessitate expert and multidisciplinary competencies to support on-site decisions.

       References

V. Calvanese, A. Zambrano, "A conceptual Design Approach for Archaeological Structures, a challenging issue between Innovation and Conservation; a studied case in ancient Pompei,  Buildings 2021, 11(4) 167, https:// doi.org/10.3390/buildings1104016.

A.Zambrano, L. Petrini, L. Ferro, M. Lualdi, S. Donzelli, V. Calvanese, G. ZuchtriegelA NEW APPROACH TO THE STRUCTURAL AND SEISMIC ASSESSMENT IN ARCHAEOLOGICAL SITES: THE DOMUS OF ORION, 18th WCEE, Milano (2024)

G. Zuchtriegel, L.Petti,. V.Calvanese, MC De Gaetano, C. Lupo, A. Spinosa, A.Zambrano, The Pompeii sustainable management model Monitoring and maintenance of cultural heritage using a processual approach,ejournal Parco archeologico di Pompei (2024).

 F. Lorenzoni, M.R. Valluzzi, C. Modena, Seismic assessment and numerical modelling of the Sarno Baths, Pompeii, Journal of Cultural heritage, luglio 2019 DOI: 10.1016/j.culher.2019.04.017

L. Gambilongo, N. Chieffo, P. B. Lourenço A comprehensive approach to assess the seismic vulnerability of archaeological sites: the Wupatki Pueblo in Arizona, Bulletin of Earthquake Engineering (2024) 22:4413-4445 https://doi.org/10.1007/s10518-024-01942-9.

M. Mariani, Particolari costruttivi nel consolidamento e restauro degli edifici in muratura: interventi sulle volte https://www.ingenio-web.it/30708-particolari-costruttivi-nel-consolidamento-e-restauro-degli-edifici-in-muratura-interventi-sulle-volte.

M. Mariani, Trattato sul consolidamento e restauro degli edifici in muratura: ⁠Tomo I: Interventi sui terreni e sulle fondazioni; Tomo II: Interventi sulle strutture in elevazione, Roma, Dei, Tipografia del Genio Civile, 2006; 

M. Mariani, Particolari costruttivi nel Consolidamento e Restauro, Roma, Dei - Tipografia del Genio Civile, 2014. 

M. Mariani, F. Pugi, COMPDYN 2023. 9th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Impulsive actions due to seismic jerk and design of reinforcements to counteract their effects in masonry buildings. Athens, Greece, 12-14 June 2023

P. Mighetto, Insula Meridionalis di Pompei, in "Bollettino degli Scavi di Pompei", 01. 2024. https://pompeiisites.org/bollettino-degli-scavi-di-pompei/insula-meridionalis-di-pompeibollettino-2024-n-01/

P. Mighetto, M. Bartolini, Il programma di riqualificazione ambientale per una nuova gestione del patrimonio archeo-paesaggistico vegetale del Parco di Pompei. Vivere il passato per capire e proteggere il presente, in "Rivista di Studi Pompeiani", XXXIV, 2023, pp. 203-207