CONTENTS FEATURES I DFI DEEP FOUNDATIONS The Magazine of the Deep Foundations Institute (DFI) is published bimonthly by DFI. 326 Lafayette Avenue, Hawthorne, NJ, 07506, USA T: 973.423.4030 F: 973.423.4031 Email: [email protected] Executive Director Theresa Rappaport [email protected] Executive Editor Virginia Fairweather [email protected] Managing Editor Emeritus Manuel A. Fine [email protected] Advertising Manager Karol Paltsios [email protected] DFI Executive Committee President, Robert B. Bittner Vice President, Patrick Bermingham Secretary, Matthew Janes Treasurer, John R. Wolosick Past President, James A. Morrison Other Trustees David Borger Maurice Bottiau Dan Brown Gianfranco Di Cicco Rudolph P. Frizzi Bernard H. Hertlein James Johnson Douglas Keller Samuel J. Kosa Kirk A. McIntosh Raymond J. Poletto Arturo Ressi di Cervia Michael Wysockey 51 Micropiles, Earthquakes and Starfish…Oh My! Morgan Eddy Engineer Eddy from Steele Foundation, LLC, writes about the performance of micropiles in an earthquake in Virginia and suggests that clusters of micropiles can act like a starfish, where the group disperses the concentrations of loading scenarios. When the forces concentrate towards a single pile, the neighboring piles step in to carry some of the burden. Designing micropile systems with this mentality can produce sustainable and resilient structural systems for acceptable performance in a rare event. DEEP FOUNDATIONS • JULY/AUG 2013 • 3 12 Testing Foundations for Major Minnesota Bridges Dan A. Brown, Paul J. Axtell and Rich A. Lamb Engineers from Dan Brown and Associates describe the results of load testing for the Minnesota transportation department on five new bridges that span the Mississippi River. The deep foundations for these structures include both drilled shafts and large diameter open-ended driven steel pipe piles. Load tests, both axial and lateral, were performed and the consultants comment on improvements in reliability, constructability and cost- effectiveness with foundation design and construction. The key to continuing improve- ments, they say, is the rational incorporation of load testing into major projects for the long-term benefit of the agency and the public. (Cover photo: David R. Gonzalez, MnDOT) O T N A S D I N N U S T O I F T U E P T E E D
