Jorn M Seitz, Dipl-Ing. This paper was first published in GE’s Noveber 1986 edition.
The increasing use of large diameter bored piles as deep foundation elements requires definitive and economical test procedures that can be used shortly after construction to evaluate their structural integrity.
Low strain integrity testing requires the recording of the pile top acceleration caused by a blow of a hand-held impact device. Strains will be small, however, but acceleration can be measured by very sensitive motion transducers.
Large imperfections or irregularities in the pile may be detected and the wave velocity gives a relative indication of concrete quality. Difficulties in record interpretation may arise from a lack of systematic investigations.
The low strain integrity testing technique is described in this Paper. Three examples are given that demonstrate the advantages and benefits from wave propagation testing as a diagnostic tool.