Remote access micropiles for Sunrise Powerlink (courtesy of Crux Subsurface) decisions needed during specification development, including risk allocation. Efforts led by Larry Johnsen of Heller & Johnsen, and former chair of the DFI Codes and Standards Committee, resulted in a task force of the Micropile Committee to propose a new section of the International Building Code specifically describing the design criteria for micropiles. Built on research efforts and consideration of published papers that helped drive acceptance of the technology, the International Code Commission accepted this new code with little modification. This may have been one of the greatest milestones for the acceptance of micropiles into commercial/private markets. Until this point, engineers were creatively adapting other code sections to micropile practice, often raising questions from reviewers and misusing sections for particular project or commercial advantages. The road to acceptance in the public transportation market was a little longer. Although the FHWA micropile manual was first released in 2000 and updated in 2005, its full acceptance and use continues to expand. A key challenge was the evolution of the transportation industry to Load and Resistance Factor Design (LRFD) method- ology and the challenges that came with defining design methods and factors to be used. It was evident that creating a new AASHTO code section for design of micropiles was not a high priority for the T15 committee in the early 2000s. So again, the joint committee stepped up and funded 100 • DEEP FOUNDATIONS • MAY/JUNE 2016 the key piece of research needed. D’Appolonia Engineering was contracted to develop a study that would help calibrate resistance factors for micropiles and intro- duce a section into the Highway Bridge Design code adopted in 2009. The com- mittee continued this effort until 2014 when the first micropile construction specification section was completed and included in the AASHTO 2015 interim revisions. Continued Progress One of the benefits of having partners from all aspects of an industry in the same discussion is leveraging the expertise and ski l l s to produc e indus t r y-wide advancements. The exchange of ideas and sharing of information in both the Micropile Committee and ISM directed research efforts by universities and professional societies to topics that were relevant to practice including buckling, grout strength, strain compatibility and connection details. The micropile market has grown over the past two to three decades in North America and around the world. The growth of application and acceptance of micropile technology offered greater opportunity for providers to identify and apply their greatest advantages rather than a few contractors all bidding on every micropile project. Further, the growth of knowledge and application stimulated (and supported) manufacturers to invest in the technology, bringing new equipment, tools and materials to market, further reducing risk to all parties. Building on the growth in this technology, the next advancement will emerge. Early adopters will take the risk, and by so doing will stand to benefit the most. Education will be an anchor for continued growth. However, delivery of knowledge will change format. Seminars will give way to online training, published case histories will give way to social media and networks of colleagues exchanging information and archiving conversations, some manual QC will become automated and delivered in real time, and one day we may find an efficient design and use for reticulated micropile systems that will again change the way we look at challenges. Acknowledgements The authors recognize all of those who have contributed significantly to the growth of micropile technology. Your efforts were rewarded through the successful and relatively rapid growth of an industry. Although we cannot list everyone that has made major contributions to this growth, we would like to recognize a few contributors who have been our mentors as well. This list includes in no particular order: Donald Bruce, Jouko Lehtonen, Thomas Herbst, Roger Frank, Ernst Ischebeck, James Mason, Jesús Gómez, Nadir Ansari, Tom Richards, John Wolosick, Tom Armour, Paul Woodfield and Scot Litke. Without their contributions, the industry would not be what it is today, nor would our careers have developed as they have. This is an abridged version of the paper “DFI Mission Executed through Growth of Micropile ceedings for the DFI 40 Annual Conference. Technology.” The full version is part of the Pro- th
