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The study of the cracking phenomena occurring in concrete arch dams represents one of the most complex challenges engineers have to face in the safety assessment of structures.
Cracks may appear in any dam body whenever in their lifetime as well as during construction. In the former case the development and growing of cracks is mainly related to operating conditions or accidental events; in the latter case the thermal effects, occurring in concrete at early age, play a key role. In literature, several modelling studies on the first topic are available; whereas realistic simulations of the construction phases of thin arch dams, based on 3D models, are rather uncommon. As the development of the hydration heat and the subsequent hardening of concrete castings may became particularly critical for this kind of dams, this paper will focus on the numerical modelling of these phenomena referring to a real case study. In particular, the development of short and long-term effects, both thermal and rheological, will be examined taking into account the real sequence of concrete castings, followed during the construction of the arch dam. The numerical procedures developed in order to automatically define the temporal sequence of concrete castings in the 3D model, as well as to assign how physical-mechanical properties of concrete change during construction, will be presented. In particular, these procedures have been defined making reference firstly to 2D and 3D simplified models in order to automatize the process and to optimise the set up of the 3D model of the real structure. The resulting “changing-in-time” stress-strain pattern will be evaluated referring to the actual crack pattern of a real arch dam.
31 Dicembre 2009
Studi su potenziali sviluppi delle energie rinnovabili (P04PROD)