The Deep Foundations Institute (DFI) has released a free, 187-page report from a workshop on quality assurance practices for acceptance of post-grouted drilled shafts. The workshop was organized by DFI in partnership with the California Department of Transportation (Caltrans), the Federal Highway Administration (FHWA), and with support from the International Association of Foundation Drilling (ADSC). The 1.5-day workshop was held in conjunction with DFI’s 40th Annual Conference on Deep Foundations in October 2015.

The workshop was organized to assist Caltrans in better understanding issues related to acceptance of post-grouted drilled shafts on highway projects. The primary goals of the workshop were to:

  • Identify and summarize the state of practice for design, construction, inspection, verification, acceptance criteria, reliability and performance of post-grouting.
  • Identify gaps and needs in quality assurance that should be addressed for successful use of post-grouting.

Workshop presentations provided state of practice overviews and perspectives from owners, engineers and contractors on acceptance of post-grouting methods for drilled shafts. Subsequent workshop discussions, attended by a small invited group of participants, focused on identifying areas of agreement and disagreement on post-grouting best practices, acceptance criteria, design and verification procedures, and inspection requirements.

Several state DOTs have expressed strong interest in better understanding the mechanisms of improvement due to post-grouting and in implementing appropriate provisions for quality assurance and acceptance of post-grouted drilled shafts. FHWA will use the results of this workshop in conjunction with its ongoing research study to formalize guidance on design, construction and acceptance of these foundation elements.

The DFI is an international association of contractors, engineers, academics and suppliers in the deep foundations industry with more than 3,300 members worldwide. For more information about the Deep Foundations Institute, visit