Restoring fragmented marble epistyles: Some critical points

The mechanical behavior of fragmented marble epistyles restored with titanium reinforcing bars is studied numerically using the Finite Element Method. The study is focused to the behavior of restored epistyles subjected to bending under uniform load along the free span of the structural element. The restoration method simulated is the one introduced a few years ago by the scientists working for the conservation of the Parthenon Temple on the Acropolis of Athens and is still under development. Attention is focused to the influence of the geometric features of the reinforcing bars as well as to the role of the cementitious material interposed between the marble and the bar. In addition, the contact properties of the marble-titanium, marble-cement and cement-titanium interfaces are also examined. To achieve the goals of the study, six numerical models are constructed considering centrally fractured prismatic marble epistyles of rectangular cross section restored with a single titanium bar, either cylindrical or threaded. The analysis reveals the critical regions, where the maximum stresses and the strain discontinuities appear and makes clear the influence of the geometrical characteristics of the reinforcing bar. Also, the crucial role of the constitutive law governing the mechanical behavior of the intermediate layer of cementitious material is enlightened.