construction phases of a concrete arch dam Massimo Meghella*, Antonella Frigerio*, Piero Masarati* 10th International Benchmark Workshop on Numerical Analysis of Dams Parigi, 16-18 Settembre 2009 * ERSE SpA Within the safety assessment of structures, the evaluation of the thermo-mechanical phenomena occurring in concrete arch dams during their construction is one of the most difficult challenges engineers are concerned with. Considering that such effects can give rise to the development and growing of cracks that might be critical for the dam safety, and that in literature realistic 3D simulations of the construction phases of concrete arch dams are rather uncommon, the Theme A proposed for the 10th Benchmark Workshop on Numerical Analysis of Dams aims to promote a thorough study of these challenging tasks so that a better understanding of the initial stress-strain pattern evolution of thin arch dams could be achieved. In this paper the numerical modelling of these phenomena referring to a real case study is presented. The development of the hydration heat and the subsequent hardening of concrete castings are considered. In particular, the development of thermal and rheological effects is examined taking into account the real sequence of the concrete castings followed during construction.