In the mid-1980s, the Joint Caisson - Drilled Shaft Committee of the ADSC and DFI wrote the Drilled Shaft Inspector’s Manual, which was published in 1989. The manual took more than two years to develop, with contributions from many leading contractors, researchers and testing practitioners of the time. It was also reviewed by a committee of geotechnical engineers from the ASFE, now known as the Geoprofessional Business Association (GBA) to ensure that it truly represented a consensus of opinion and the state of the practice at that time. In 1990, DFI published Dynamic Monitoring and Analysis of Pile Foundation Installations, a guide to high-strain dynamic testing of driven piles. The guide was developed and published by the then-extant Continuing Education Committee as one of the official texts for the DFI shor t course Design, Analysis and Test- ing of Piles and Drilled Shafts. The guide presented an overview of the methods available at that time for dynamic measurement and analysis of impact-driven piles during installation and restrike for predicting long- term performance. Al so in 1990, the Augered Cast-In-Place Piles (ACIP) Manual was pub- lished by the ACIP Pile Committee. Again mem- bers of the Inspection and Testing Committee contributed to establish the state of the practice. Other contributors included contractors, engineers, university researchers and equipment or material suppliers. This manual was updated in the second edition published in 2003. The ACIP Piles Manual was followed in 1994 by the Augered Cast-In-Place Piles Inspector’s Guide, again written by the ACIP Pile Committee, with contributions from leading contractors, engineers and testing practitioners. This guide was updated and a second edition published in 2010. The Inspection and Testing Committee morphed into the current Testing and Evaluation Committee, and after many years of supporting other committees’ publica- tions, the Testing and Evaluation Committee collaborated with the Drilled Shaft Commit- tees of both ADSC and DFI, to finally publish the Manual for Non Destructive Testing and Evaluation of Drilled Shafts in 2004. One of the newest DFI committees, the Tiebacks and Soil Nailing Committee, collaborated with the ADSC Anchored Earth Retention Committee to publish the Soil Nailing Guide Specification in 2010. Although the load testing typically performed on tiebacks and soil nails is not nondestructive in the normally accepted sense of NDT, if the element does not fail, then the test can be considered nondestructive, and members of the Testing and Evaluation Committee contributed to the guide. The amount of committee work that goes into writing, reviewing and achieving consensus in technical documents covering the complexities of deep foundation construction should not be underestimated, and the commitment of those members involved should be appreciated by all who benefit from their documents, which are all available via the DFI website, www.dfi.org . In addition to the very informative committee documents, the papers from each one of the DFI conferences are compiled into Conference Proceedings documents that are also available through the DFI website. Thus, there is an enormous wealth of knowledge distilled in the various DFI publications, and as the value of DFI mem- bership became apparent overseas, the demand for international chapters grew. The first Regional Chapter established was DFI Europe, in 2005, fol- lowed by DFI Middle East in 2010, and DFI of India in 2013. Pile Driving Analyzer 2007 (Courtesy of GRL Engineers) In 2011, the Guideline for Interpretation of Nondestructive Integrity Testing of Augered Cast-in-Place and Drilled Displacement Piles was published as a result of collaboration between the ACIP Pile Committee and the Testing and Evaluation Committee. The guideline was written to address specific industry concerns about the applicability of low-strain integrity testing to ACIP piles, which tend to have an irregularly over-sized cross-section when constructed in soft soils. This generates test data that is sometimes difficult to interpret, and tends to increase the likelihood of a false positive indication of a flaw or defect when reviewed by an inexperienced analyst. Mutual Benefits Just as the DFI membership benefitted from the input of the NDT practitioners, the NDT practice benefitted from the experience of the DFI members and the deep foundations industry as a whole. Some of the more important benefits were, and still are, the networking and collaboration opportunities afforded by DFI conferences and seminars. Researchers and practitioners with similar concerns quickly found common ground, and significant advances in both hardware and analytical procedures resulted. Most of these advances have been incremental in nature, as the practitioners gained experience with various construction methods and site conditions, but some new applications and technologies emerged as a result of the networking facilitated by DFI. Members of DFI were instrumental in organizing and analyzing several “Class A” prediction contests, in which a number of drilled shafts were constructed with controlled defects that were unknown to the testing practitioners that were invited to DEEP FOUNDATIONS • MAY/JUNE 2016 • 107
