Pile Integrity Test:

Pile integrity testing” may be  applied to any  concreted pile (e.g. concrete piles, drilled shafts, auger cast piles, concrete filled pipe piles).  The  test  requires the impact of a small hand held  hammer on  the  shaft  top and  the  measurement of the shaft  top  motion  (acceleration  or velocity).  The input  compression  wave  from the hammer is  reflected  from pile toe (or a defect) and  returns  to  the pile top at a time related to the speed of travel of the wave in the pile material.

    The pile top velocity is displayed as a function of time with an exponentially increasing magnitude where high  soil friction forces are present, such that the  pile toe reflection is   enhanced.  Several   records  with  consistent  signals  should  be   averaged.  The averaged , amplified velocity  is  the  standard  result  of  the Pulse  Echo Method. The  force  as  a  function  of  time  may  also  be  depicted,  if   available,  which  provides    additional information as to the pile quality near the pile top.

   The Transient Response Method result shows  the  ratio of velocity to force transforms for all relevant frequencies.  This curve is called Mobility. It  should  be shown together with the  related  low  frequency  pile  stiffness.  These Transient Response results are only available if hammer force was measured.