Évaluation de la réponse sismique des structures annexes aux barrages-poids au moyen de la méthode de l'accélérogramme modifié

The evaluation of the seismic behaviour of gravity dam appurtenant structures is of major importance both in the preliminary design stage and in the studies of their rehabilitation. This evaluation is complex especially when considering dam-reservoir interaction. The modified accelerogram method (MAM) is one of the simplified techniques that can be used to account for fluid-structure interaction and simplify the verification of the dynamic behavior of structures attached to gravity dams. This work presents a linear dynamic analysis of a dam-reservoir system subjected to three earthquakes of different frequency contents, using the finite element method. The results of the analyzes are examined in terms of the floor spectrum which is an important element in the verification of the structures annexed to the gravity dams. First, the reservoir is modeled by fluid elements to consider the hydrodynamic loads generated by the fluid-structure interaction. The seismic excitation that the dam-reservoir system undergoes is defined by an original input accelerogram. This is then replaced by a new input accelerogram modified using MAM and applied to a single dam without reservoir to take into account the fluid-structure interaction.