2017 Paper Competition Winners DFI and the DFI Educational Trust annually hold a Student Paper Competition and a Young Professor Paper Competition as a means to bridge the gap among practice, studies and research. For both competitions, the topics and content of the papers must be germane to the design and construction of deep foundations and excavation systems. To qualify, the young professor must be a full-time, entry-level faculty member of an accredited college or university, who is engaged in teaching and/or research in any of the professional fields including engineering, construction or geological sciences. For students, eligible participants must be enrolled in an accredited college or university in an undergraduate or graduate engineering or construction program. outward into the annulus. Depending on slurry type, the radial flow may produce laitance-filled creases or channels that project the reinforcing cage configuration to the outer surface of the shaft. The flow pattern (and creases) can affect filter cake thickness, cover quality and propensity for corrosion. A direct correlation between the use of bentonite slurry and laitance channel formation was identified, which indicated a high propensity for corrosion and lower strength. The drilled shafts constructed using polymer behaved in a similar manner to the shafts constructed using water, neither of which indicated a heightened propensity for corrosion or reduction in strength. There are two runners-up for the Student Paper Competition. Jennifer Ostrowsky, P.G., Utah State University for “A for Offshore Wind Turbines: Cyclic Loading and Liquefaction.” In addition, four student papers are receiving special recognition. • “Statistical Analysis of Design Method for the Axial Capacity of Single Driven Piles in Glacial Tills,” by Markus Jesswein, EIT, Ryerson University • “Physical Modelling of Lime Stabilisa- tion in Soft Soils Around Deep Exca- vations,” by Jignasha Panchal City, University of London • “Challenges Associated with the Regional Calibration of Resistance Factors for Drilled Shafts,” by Philippe Kalmogo, Iowa State University • “Field Study of Blast-induced Lique- faction Dragloads on Drilled Shaft Foundations,” by Elvis Ishimwe and Richard A. Coffman, associate pro- fessor, University of Arkansas Young Professor Paper Mobley and Costello, student paper winners Student Paper Competition The 2017 Student Paper Competition winners are Sarah Mobley, P.E., doctoral student, and Kelly Costello, E.I., doctoral candidate, from the University of South Florida in the department of civil and environmental engineering. Their winning paper, “The Effect of Slurry Type on Drilled Shaft Cover Quality,” presented the findings of laboratory experiments performed on 24 tremie-placed concrete specimens that investigated the correlation between slurry type (bentonite, polymer and natural slurry) and laitance channel formation. Concrete placed in a drilled shaft using the tremie method first fills a portion of the shaft within the reinforcement cage prior to flowing beyond the cage and radially New Approach for Evaluating the Ductility, Volumetric Stiffness and Permeability of Cutoff Wall Backfill Materials,” and Martijn van Wijngaarden, M.Sc., Delft University of Technology, for “Gravity Based Foundations Competition The 2017 Young Professor Paper Compe- tition winner was Arash Khosravifar, Ph.D., P.E., from the geotechnical engineering group in civil and environmental engi- neering department at Portland State University (PSU). In the winning paper, “Development of a Design Guideline for Bridge Pile Foundations subjected to Liquefaction-induced Lateral Spreading”, Dr. Khosravifar, along with his co-author Jonathan Nasr, graduate student researcher at PSU, describe the development of new equivalent static analysis (ESA) methods that combine inertial and lateral spreading loads for estimating elastic and inelastic pile demands. Effective-stress nonlinear dynamic Ostrowsky, student runner-up analyses (NDA) were performed for piles in liquefiable sloped ground to assess inertia and liquefaction-induced lateral spreading in long-duration versus short-duration seismic excitation. The authors performed a parametric study using a wide range of input motions and motion durations from subduction and crustal earthquakes. The NDA results indicated that the pile DEEP FOUNDATIONS • NOV/DEC 2017 • 35
