Long Piles Integrity Trough Impact Echo Technique.

Abstract

The main objective of this paper is to evaluate the capabilities of the nondestructive
impact-response method in detecting the existence of defects in long piles.
The impact-echo technique, based on the use of transient elastic waves, was developed many
years ago for non-destructive detection of defects in piles and structures. Moreover, is
recognised in the specialised literature that this method could be applied confidently for piles
with length/diameter relationship up to 20. However, with the development of hardware in
computers and new sensors and dynamic equipment, it is possible now to use this method for
long piles. In this paper, piles of length/diameter relationship of approximately 40 are
studied.
A numerical-experimental study was carried out. Finite element models 1D and 3D were
performed for piles including the surrounding soil and defects type necks and bulbs.
Subsequently, experimental studies were carried out to verify the finite element models using
similar piles. These experimental studies were carried out in the air and soil, and impact
responses were analyzed in both time and frequency domains. It was shown that the results of
the experiment were in agreement with those of numerical studies, and the accuracy of the
impact-echo method was influenced by the type, size and location of defects. In addition, it
was also revealed that the method could be applied for long piles.