Roberta Fonti1 and Michele Candela2
1)  TU München, Lehrstuhl für Restaurierung, Kunsttechnologie und Konservierungswissenschaft
Oettingenstr. 15, Munich, Germany
2)  University Mediterrenea of Reggio Calabria, PAU Department
Melissari, 1 Reggio Calabria, Italy

Keywords: Masonry vault, Extradossed masonry rib, Tie-rod, Eccentric axial load, Reconstruction, repairs.

Abstract. This paper addresses the issue of reconstructing a large span masonry vault in modern times by using the example of the Neapolitan convent of Santa Maria in Gerusalemme. This heritage building, located in the World heritage site of Naples, was designed and built during Renaissance by using natural stones typical for the Neapolitan area. Following the extension of the Incurabili’s hospital (1918), the monastery was partially ruined. Especially, the hall of the refectory was to a great extent demolished aimed at providing the ancient clinic with rooms especially for tuberculosis-infected patients. The refectory, which was covered by a large barrel vault, was built by using tuff stones both for the vault and the walls. Groin on the extrados also exists. Technical concerns affecting the practice of repairing by using traditional building techniques are reported through the paper, along with measures for designing abutments and structural thicknesses while reducing vulnerability to eccentric axial loads on supports. Thus, the phases of the design and reconstruction of the vault of the refectory are illustrated through the paper aimed at providing a means of integrating new masonry members into existing masonry buildings, along with measures for calculating tie-rods while resisting eccentric axial loads. To achieve this goal five objectives are formulated here and addressed through the paper. These being: (i.) The rediscovery of the use of lunette in the static of masonry vaults to design abutments; (ii.) The use of groin on the extrados to redirect axial loads on walls; (iii.) To interlock existing and new masonry while carrying loads at work; (iv.) To bond structural members and filling materials on account of potential defect of execution due to deficiency of specialized labor – as traditional building techniques fell from use. (v.) The use of ties to resist lateral forces in the face of eccentric axial loads.