Geometry and Stability of a Double-shell Dome in Four Building Phases: The Case Study of Santa Maria Alla Sanità in Naples

ABSTRACT

This research work provides a stability study for a double masonry dome during its construction process and, a consideration of the possible effects that the procedure followed for building the structure has on its current mechanical behaviour. In particular, the analysis is carried out on the Baroque dome of Santa Maria alla Sanità in Naples, a relatively small dome with a span of 12 m. The main contribution of the paper consists of making a hypothesis about the different phases of construction and demonstrating that the dome was in equilibrium during these different phases. This aspect has been rarely considered when analysing historical structures. The theoretical framework assumed refers to Limit Analysis in which the masonry is modelled as composed of rigid-unilateral material. To assess the stability of the dome, the study proposes an equilibrium analysis performed both graphically and analytically, by using the graphic statics and the membrane analysis. The results obtained from the two methods are also compared, at each stage of construction. Besides the classical graphical methodology based on the slicing technique, the membrane equilibrium solution provides a wider repertoire of equilibrium states, since it allows for biaxial stress fields and is here implemented with a new method for which the surface and the stress potential are both approximated through simplicial surfaces based on the same triangulation. This more refined analysis confirms the results obtained through graphic statics giving wider geometrical safety margins and a more detailed interpretation of the non-axisymmetric loading cases

KEYWORDS:

• Architectural heritage
• construction history
• equilibrium approach
• graphic statics
• limit analysis
• masonry domes
• membrane analysis
• under construction

Acknowledgments

The authors would like to thank Prof. Santiago Huerta for his support and helpful comments on earlier versions of this research.

This research has been partially supported by the “AIM: Attraction and International Mobility”, PON R&I 2014−2020 Campania, n. 1849854 – 3 “Smart Secure and Inclusive Communities”. CUP: E66C19000230005

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

¹ In 1569, a violent storm brought to light the catacomb of San Gaudioso. This cave had been a place of pilgrimage until the ninth c., when the Saint’s body transferred to the monastery of Constantinople dedicated to him. In 1583, the Archbishop of Naples, Cardinal Paolo Burali D’Arezzo, donated the catacomb to the Dominican friars (Ceci 1920).

Additional information

Funding

This research has been partially supported by Italian Ministry of University and Research (MUR) through the  project “AIM: Attraction and International Mobility”, PON R&I 2014−2020 Campania, n. 1849854 – 3 “Smart Secure and Inclusive Communities”. CUP: E66C19000230005.