CORRELATION BETWEEN SETTLEMENT OF EMBANKMENT DAMS AND GROUND MOTION INTENSITY INDICES OF PULSE-LIKE RECORDS

Near-fault seismic records strongly influenced by forward directivity are characterized by one or more large pulses in velocity time histories. The characteristics of these records are significantly different from ordinary records. This study evaluated the correlation between the intensity indices of pulse-like ground motion and crest settlement of embankment dams and their ranking according to quality was evaluated. The seismic behavior of five embankment dams with different heights was investigated under 105 pulse-like and 20 ordinary ground motions with over 680 nonlinear time history analyses. The results showed that inelastic structural ground motion intensity indices are more applicable than elastic indices to predict the settlement of embankment dams. The proposed inelastic structural ground motion intensity (IMPD) calculates the mean permanent displacement of a single degree of freedom (SDOF) system over a period of 0.2T1 to 1.5T1 (where T1 is the natural period of the dam) based on Newmark’s method using a decoupled approximation and deformable SDOF instead of a rigid block system. The non-structure ground motion intensity index IVA (where IVA is the square root of the product of peak ground velocity and plain integral of the squared acceleration) is proposed as a good predictor for the nonlinear response of embankment dams.