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.
