Date Project 1996-98 Williamsburg Bridge, NY 2004 1998 IBM, NY Mandalay Bay, NV 2001 Spallation Neutron Source, Oak Ridge, TN Significance Retrofit foundations 1,500 piles completed rapidly in difficult ground Underpinning of a tower while it was continuing to settle High capacity piles in karst 2000-03 Richmond San Rafael Bridge, CA Strengthen bridge piers under water Table 2: Mega Projects that influenced the growth of the micropile market in the U.S. Addressing the Technology Needs The California Department of Transpor- tation (Caltrans) responded to the Loma Prieta tragedy by conducting a full-scale micropile load test program, and in 1994, the U.S. Department of Transportation/ Federal Highway Administration (FHWA) commissioned a state-of-practice review on the use of small-diameter drilled micro- piles. The four-volume report was pub- lished in 1997. As part of this program, the FHWA commissioned an international peer review group to advise the research team. DFI and ADSC members recognized Installation of micropiles for a scenic walkway on Mt. Dachstein, Alps (EL 2,900 m) (courtesy of Andreas Brandner) Seismic retrofitting of bridges became a critical need after the tragic collapse of multiple structures during the 1989 Loma Prieta earthquake. Federal agency and professional societies recognized the potential for micropiles to fill this need, and attention focused on the lack of micropile performance data and design and construction guidance for such works. Appreciat ion of the potent ial advantages of micropile systems also grew internationally. With the expiration of the initial Italian patents for the GEWI pile, by DYWIDAG Systems, and other proprietary systems, micropiles saw increased use in both Europe and North America. The devastating Kobe earthquake in Japan in 1995 highlighted the need for seismic retrofitting systems. And in Scandinavia, small-diameter drilled systems were needed for repairing existing structures and for new-build works in city-center sites underlain by deep deposits of sensitive clays overlying bedrock. 98 • DEEP FOUNDATIONS • MAY/JUNE 2016 the industry and market advantages of forming technical commi t tees on micropiles. The Joint ADSC-DFI Micropile Committee (Micropile Committee) was established in 2001 and comprises multi- disciplined membership of engineers, contractors, manufacturer and equipment suppliers, researchers, and owners based mainly in North America. The core group of FHWA state-of- practice researchers and peer-review group members evolved into the International Workshop on Micropiles (IWM), a forum for exchanging knowledge, experience and advice to those interested in developing micropiles in other areas, conditions and applications. IWM grew to over 80 active delegates and positioned itself as a center of knowledge on techniques and use of high- capacity micropiles. In 1997, the first IWM was organized by FHWA, the original delegates and DFI to transfer technology to colleagues in Japan on seismic retrofitting practices following the devastating Kobe earthquake. A total of 12 workshops have been organized since the first, one every 18 to 24 months. Delegates from over 25 countries have participated. To foster permanence of this group and highlight its increasing role as a repository of micropiling resources, IWM incorporated formally into a stand-alone society as the International Society of Micropiles (ISM) in 2006. In 2012, ISM, DFI and ADSC formed an a l l i a n c e t o l e v e r a g e t e c h n i c a l , administrative and networking resources to better position themselves to address the global needs related to the micropile industry. ISM operates as an entity within the Micropile Committee, continuing to work closely to further technology transfer across the globe. Guidance Documents and Training Courses FHWA and IWM advanced the four-volume state-of-the-practice document into a useful guide for state transportation agencies to implement design and construction projects with micropiles. FHWA Micropile Design and Construction Manual (Imple- mentation Manual) was published in 2000 (updated in 2005), as the multi-million dollar international research effort FOREVER (1994-2000) was wrapping up. The FOREVER report was translated into English and published by ADSC in 2008. In 2002, FHWA commissioned ADSC to develop the National Highway Institute training course based on the design and construction manual. Joint committee members have taught this short course throughout North America since 2004. Following years of basic short courses Slope stabilization for a gas pipeline in Maharashtra, India (courtesy of Andreas Brandner) and seminars by ADSC and DFI, a more advanced course was delivered in 2009. Referred to as Micropiles 201, it covers
