Concrete dams are subject to stresses which can involve cracking phenomena during their building, in the regular operation and with high intensity forces (due to exceptional events such as earthquakes, floods and landslides, to significant thermal variations or aging and degradation processes, such as the alkali-aggregate reaction). The analysis of these phenomena is fundamental in the studies and assessments of dam safety, mainly for the existing structures.

Modelling the cracking behaviour of concrete is a complex topic and it can be dealt with two approaches, based on finite element method: the smeared crack model allows to identify the damaged areas by assigning suitable constitutive laws to the continuum; the discrete crack model, based on fracture mechanics, allows to describe the localized formation of cracks, considered as geometric discontinuities through the continuous medium.

To identify the potential and the limits of the two approaches in the study of the structural response of concrete dams, a preliminary review of the technical literature has been developed.

In the frame of the two approaches, the Concrete Damage Plasticity model (CDP) and the eXtended Finite Element Method (XFEM), both available in commercial finite element software Abaqus, were considered as the most suitable for the study of concrete dam behaviour.

To apply and compare the two approaches, two case studies were identified: the static analysis of a three-dimensional beam subject to bending and the two-dimensional dynamic analysis of Koyna gravity dam subject to horizontal and vertical seismic forces. These first case studies have shown the potential of both approaches, but they have also highlighted some drawbacks that will require further investigation.

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