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  (I MPD)  calculates  the  mean permanent displacement of a single degree of  freedom (SDOF) system over a period of 0.2T 1  to 1.5T 1  (where T 1 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 I VA  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.