Stability analysis and seismic vulnerability of large masonry domes

This research specifically deals with the issue of the stability of the dome of St. Francesco di Paola (1816) in Naples. It represents the largest dome of its type and is the most significant example of Neapolitan Neoclassical architecture and as such generates great interest due to its solid and impressive structure. Structural analysis of the dome is performed using Heyman's Theory of Limit Analysis for masonry structures and, in particular utilises traditional methods that make use of a static approach based on graphic statics and on the interpretation of thrust lines of stone arches. As is well known, displacements are common in historic masonry structures due, for example, to consolidation of materials, imperfections in construction or differential settlements in foundations. The structural method applied in this work does not aim to define the cause of these displacements but rather seeks to understand their influence on the stability of the construction. With this perspective, in addition to the static analysis, a kinematic analysis approach has been necessary to enable an understanding of the range of possible movements of the masonry structure. Thus, the research of the dome’s minimum thrust has been checked both by static and kinematic approaches in order to assess the safety of the construction. Furthermore, the effects of earthquakes have been explored. By introducing horizontal forces proportional to the weight, it has been possible to assess dome stability under horizontal actions and to determine the limit value of the dome inclination for which the masonry is still entirely compressed. © 2019, International Masonry Society. All rights reserved