Kevin Johnson, a Ph.D. candidate at the University of South Florida, in the department of civil and environmental engineering, is the winner of the Deep Foundations Institute (DFI) Educational Trust 2015 Student Paper Competition.
Johnson’s paper, “Analysis of Thermal Integrity Profiling Data for Drilled Shaft Evaluation,” discusses the most recent nondestructive test method to gain widespread popularity in post-construction evaluation of drilled shafts.
Thermal Integrity Profiling (TIP) detects anomalies across the entire cross section of a shaft, as well as providing a measure of vertical cage alignment. TIP generally allows for straightforward interpretation of data, but with two exceptions: near the ends of the shaft where heat can escape both radially and longitudinally, and where drastic changes in the surroundings are encountered.
Methods for analyzing these portions of data exist, but can often involve tedious levels of parameter iterations and trial-and-error thermal modeling. Therefore an extensive study of model results is analyzed and compared with data collected from field tests. Johnson’s paper provides an overview of the analysis techniques used to convert the measured temperature profile to a shape profile, shows how thermal modeling can be used to track the effects of time on the analysis and concludes with case studies that demonstrate the findings.
Johnson’s research focuses on drilled shafts and also includes quality assurance of drilling slurries for drilled shaft construction, development of an effective splicing method for pre-stressed piles and use of stainless steel strands in pre-stressed piles. Johnson holds bachelor’s and master’s degrees from the University of South Florida and, prior to starting his doctoral studies, he worked for a concrete construction company for six years.
The first runner-up for the Student Paper Competition is Diego A. Aguirre from North Carolina State University. His paper is titled "Soil-Structure Interaction of Reinforced Concrete-Filled Steel Tubes."
The awards were presented at the DFI 40th Annual Conference on Deep Foundations in October 2015, in Oakland, Calif. Johnson presented his paper to conference attendees.
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 www.dfi.org.