Video Imaging Methodology for Estimation of Pile Capacity

Abstract

Piles have been used for generations in areas with weak soil conditions to reinforce existing ground or to support bridges and structures. As the piling industry increased over these years it was necessary to develop prediction methods to optimize designs and provide cost savings in material and man power. Multiple predictive methods exist, in Ontario Ministry of Transportation (MTO) Modified Hiley Formula, further referred to as Modified Hiley, is used to estimate pile capacities during an installation program and provide a level of confidence in the design that was selected. Parameters required to generate this estimate are historically obtained with a pen and paper and ruler while standing below the pile driving equipment. Being inherently unsafe due to the noise and potential for equipment failure another method was devised during this research using high speed cameras and post processing techniques. The first phase the research consisted of field data acquisition and collection of the pen and paper plots and of high speed video. This was followed by writing of computer code to convert the highspeed video into usable and legible data plots. The second phase of research compared manually generated plots to plots generated using the highspeed camera equipment and it was found that an excellent correlation existed. Based on this correlation, subsequent parameters that were once measured manually or calculated with a timer were instead extrapolated from a plot generated by the post processing software. The third and final phase of research used the newly gathered data from the high-speed camera equipment to calculate a predicted pile capacity for the MTO Modified Hiley, FHWA Gates and ENR Bearing formulae. All variables that required field data were populated and predicted pile capacities were computed without issue. Despite the introduction of the post processed high-speed videos, it was found that this method could be used as a substitute for the traditional pen and paper methods used today with further testing.