Modelling issues in the structural analysis of existing concrete gravity dams

Modelling aspects on the evaluation of seismic safety assessment of concrete dams assume great importance from different points of view, such as modelling approach, material properties, fluidstructure and soil-structure interaction. International standards and guidelines provide different indications concerning modelling, but they do not clarify what is the most suitable operating strategy to be adopted in the study of these structures. In the case of gravity dams, the model selection are commonly considered of secondary interest in the literature, because their simple geometry leads to the use of 2D models. This paper addresses the effects of the uncertainties related to the model typology and the definition of the material properties distributions. The work is based on an experimental design performed through latin hypercube sampling. This method is developed by changing the modelling strategy, the geometry and the material properties, in order to compare the behaviour of different models. This study highlights the great importance of the selection of 2D or 3D modelling strategy for the evaluation of the structural behaviour of gravity dams and makes possible to determine the influence of these assumptions on the final results in terms of prediction of the structural behaviour.