Gordon Cameron, PhD research student, Napier University and Tim Chapman, associate director, Arup Geotechnics. This paper was first published in GE’s February 2004 edition.
The performance of a bored piled foundation is affected by the construction quality of the individual piles comprising the piling system. For the purposes of quality assurance, a programme of non-destructive integrity testing (NDT) is usually implemented on a specified percentage of the working piles. Traditionally, the proportion of piles to be tested is decided upon by the foundation designer based on site-specific knowledge, engineering judgement and his prior experiences of NDT. This paper shows how the use of statistics and probability theory may help influence this decision.