INTERPRETATION OF PILE INTEGRITY TEST RESULTS OBTAINED FROM MODEL CONCRETE PILES HAVING TWO DEFECT LOCATIONS

Abstract

The most common query for piles is that whether their integrity is acceptable. Another
problem that has been rarely questioned is that whether a minor defect under a major defect is properly
detected. This study constructed model concrete piles having the dimensions of 0.15 by 0.15 by 5.00 m with
two defects intentionally created at 2.50 and 3.50 m from the pile top. The first defect was created to have a
constant β value of 40%; while the second defect was varied such that the β values were from 95, 90, 85, 80,
65, 50, 35, and 20%. A pile integrity testing equipment was used to detect those defects; and the results were
compared to the actual ones created. Testing was conducted on the piles being in the air and under the ground
in order to observe whether skin friction would affect the signals. For the first defect, it was found that the
average measured β values for both defects are about 76% and 89% higher than those of the actual ones. This
is an important factor that engineers should bear in mind when interpreting the signals from a report. For
instance, a defect reported is probably less than what has happened to the pile. In the case of the second
defect, the results revealed that if a β value is 89% and higher, the pile should be acceptable. However, if it is
lower than 89%, other types of pile integrity testing should be carried out to clarify the result.