On the origin of the cracks in the dome of the Pantheon in Rome

Filippo Masi (1) , Ioannis Stefanou (1) , Paolo Vannucci (2)

1 navier umr 8205 - Laboratoire Navier
2 LMV - Laboratoire de Mathématiques de Versailles

In this paper we aim at giving a contribution to a problem that has been the subject of previous studies since some decades: the reason and period of formation of the meridional cracks that affect the dome of the Pantheon of Rome. This problem is investigated using a detailed three-dimensional finite-element simulation in which material nonlinearities, as well as a plausible sequence of the construction stages, are modeled. In particular, we show that concrete shrinkage, together with gravity may have been the main mechanical causes of the cracks in the early phases of the building’s life. Unlike previous studies on the matter, that have largely inspired our research and where simplified 2D finite element models of the Pantheon were used, we make use of a detailed 3D model of the Pantheon’s structure, that takes into account for both the particular geometry of the building, and namely the presence in the dome of a coffering and of caveas, and of the differences in the materials. The nonlinear numerical simulations, in addition, aim at reproducing, through different steps, the (probable) true constructing sequence of the dome, in order to obtain numerical results as much as possible close to reality. The results of our simulations show a rather surprising correspondence with the actual state of the dome: in fact, the overall pattern of the cracks so found is in a very good agreement with the real one, for both the number of the cracks and their extent, which shows that concrete shrinkage may have been the true reason for the presence of the meridional cracks. We have also investigated the role of the stepped rings that exist in the outer part of the dome; we show in this case that some previous studies are not necessarily contradictory, but rather complementary.

Mots clés: Monumental structures; Pantheon in Rome; Roman concrete; Cracks

Domaines: Mécanique [physics.med-ph]; Mécanique des structures [physics.class-ph]

Filippo Masi, Ioannis Stefanou, Paolo Vannucci. On the origin of the cracks in the dome of the Pantheon in Rome. Engineering Failure Analysis, 2018, 92, pp.587-596. ⟨10.1016/j.engfailanal.2018.06.013⟩. ⟨hal-01719997v3⟩