Following an overview of pertinent literature, this paper presents a new methodology for estimating seismic coefficients for the performance-based design of earth dams and tall embankments. The methodology is based on statistical regression of (decoupled) numerical data for 1084 potential sliding masses, originating from 110 non-linear seismic response analyses of 2D cross sections with height ranging from 20 to 120m. At first, the methodology
estimates the peak value of the seismic coefficient k_hmax as a function of: the peak ground acceleration at the free field, the predominant period of the seismic excitation, the non-linear fundamental period of dam vibration, the stiffness of the firm foundation soil or rock layer, as well as the geometrical characteristics and the location (upstream or downstream) of the potentially sliding mass. Then, it proceeds to the estimation of an effective value of the
seismic coefficient k_hE, as a percentile of khmax, to be used with a requirement for pseudostatic factor of safety greater or equal to 1.0. The estimation of k_hE
is based on allowable permanent down-slope deviatoric displacement and a
conservative consideration of sliding block analysis.