A user-friendly digital tool for the structural assessment of historic domes: the case study of Saint Peter in Rome

This paper presents a digital tool for the rapid structural assessment of historic masonry domes. It is especially suited for masonry domes that present long meridian cracks, ergo each partitioned element governed by a pushing failure mode. The proposed procedure considers a Heyman's no-tension mechanical model has been implemented within a commercial user-friendly visual programming environment. The numerical approach consists of a parametric modelling of the failure mechanism and, therefore, exploring the domain of possible solutions using the theorems of the limit analysis. Hence, a heuristic search method is subsequently adopted to refine the geometry of the collapse mechanism and to compute the value of the horizontal trust. The validation of the developed approach has been achieved considering the Saint Peter's dome. As reported in the literature, the behaviour of the Saint Peter's dome gradually shifted from a rigid shell-type - stiffened by hoop stresses -, towards a pushing type of dome partitioned by long meridian cracks. The study also evaluated the structural integrity of the drum. In converse with more time-consuming and advanced methods of analysis, the present procedure allows the users to perform a structural assessment of a historic masonry dome in a fast and computationally efficient manner. The developed digital tool will be freely available from a web archive hosted by the University of Minho and, therefore, easily able to reach students, researchers and structural engineers.