Seismic analysis and performance evaluation of hardfill dams

Faced symmetrical hardfill dams (FSHDs), are increasingly used worldwide, yet their seismic behavior remains insufficiently documented. This study investigates the seismic performance of FSHDs through nonlinear three-dimensional and two-dimensional finite element analyses, accounting for staged construction, reservoir impoundment, dam-canyon-reservoir interaction, and strong cyclic earthquake loading. The 55 m-high Filiatrinos dam in Greece is analyzed as the main case study, while additional 100m- and 150m-high dams are examined to evaluate the effect of dam height. A complementary two-dimensional parametric study is performed for a typical 100m-high dam to assess the influence of canyon stiffness, excitation intensity, and earthquake frequency content. The constitutive representation of hardfill with the concrete damage plasticity model is verified by comparison with an elastoplastic Mohr–Coulomb model with tension cut-off calibrated to the same strength data, yielding nearly identical results. The results show that, under seismic loading, the dam body remains predominantly in compression, while tensile stresses develop mainly near the upstream toe, downstream toe, and dam-abutment interface. The resulting damage remains localized and does not compromise global stability in the cases examined. Dam and slab deformations are small, indicating satisfactory structural integrity and limited joint opening. Dam height is found to increase crest accelerations, tensile stresses, and tensile damage extent. Foundation stiffness also has a strong influence, while stiffer canyon rock increases acceleration amplification and softer foundations increase displacements and materials damage. Incremental dynamic analyses further show that damage becomes increasingly pronounced with excitation intensity, while different ground motions scaled to the same PGA still produce different displacement, stress, and damage levels. Overall, FSHDs are shown to exhibit favorable seismic performance when properly designed and constructed, with tensile behavior governing the performance of taller dams.