It was interesting to read the paper 'Foundations for the future' in the March issue of NCEI.
It did appear that most of the testing techniques suggested were semi-destructive, such as coring in the side of the pile as well as coring to the base of the pile to detect faults. I was surprised that the paper did no refer to any non-destructive tests as I understand there are numerous NDT techniques available for the testing of piles in the UK. There is I believe a project report by TRL on Advice on integrity testing of piles, and a number of companies which offer services for the NDT testing of piles.
There are systems which will not only give the integrity of the piles but will give a reasonably accurate assessment of the load/ deflection value, based on work by Davis and Dunn and in later years by Higgs et al. Though the systems may no be regarded as giving 100% accuracy, the results when compared to a static load test are generally to within 10% of the results of these tests in the elastic range. As in the scenario of using existing piles, the design would generally only consider the elastic range of the piles and as such the information gained from NDT tests would be valuable to the designer.
Finally, I wonder if the authors did consider the use of such techniques and if so, the reasons why they didn't try them.
DJ Tongue (AM) Melbourne, Victoria 3429, Australia