Analyses sismiques des barrages-poids: effets de l'irrégularité de l'interface barrage-fondation sur la stabilité au glissement et de l'interaction fluide-structure sur l'amplification dynamique

This work proposes two new methodologies to perform seismic safety assessment of gravity-dams. First, special non-linear finite elements are developed to study the sliding of the dam due to non-linear behavior at the dam-rock interface. Secondly, seismic floor acceleration demands within gravity dams are analyzed using floor response spectra, taking into account various modeling assumptions of fluid-structure interaction. The special interface elements developed in this work allow the dam to slide and rock over its foundation while obeying Mohr-Coulomb failure criterium including cohesion and tensile strength at the interface. The methodology is presented so that the proposed interface elements can be efficiently implemented by practicing engineers in a commercial software. Subsequently, the developed interface elements are used to investigate the sensitivity of the seismic response of an existing gravity dam (located in Quebec) to various non-linear modeling assumptions. The gravity dam is subjected to various seismic inputs with horizontal and vertical components. The non-linear response of the dam is examined through stress distributions, sliding safety factors, cracking lengths and residual displacements at the dam-rock interface. Finally, a discussion comparing non-linear analyses to simplified methodologies to assess the safety of a gravity dam is provided.