Abstract
Helical piles are progressively evolving as a viable and cost effective deep foundation solution over traditional deep foundation systems. Historically, helical piles were generally of a small size mainly used to resist light loads, whereas today helical piles are becoming larger in size and used over a diverse range of industries and geological settings, involving higher applied loads in more complex applications. Quality control of the helical pile typically consists of measuring torque during installation, and performing a static load tests as a way to correlate the torque to capacity relationship. High-Strain Dynamic Load Testing (HSDLT) of helical piles has become an alternate method to the often costly and time consuming traditional “top-down” static load testing. HSDLT has been performed for decades on driven and drilled deep foundations, and recently the technology has been applied to helical piles as well. Dynamic tests can be performed relatively quickly to develop the load versus displacement curves and to evaluate the ultimate helical pile capacity. Several HSDLT’s were performed on helical pile foundations for The Dow Chemical Company as part of the building 949 addition located in Midland Michigan, and the results of the testing are presented herein as a case study, which includes a discussion on the analysis methods.