Productivity and cost assessment for continuous flight auger piles

Continuous flight auger (CFA) piles do not receive sufficient research attention although they are widely used in the United States, United Kingdom, and other countries in the world. Therefore, this paper focuses on describing the CFA pile installation features, exploring its construction methods, and determining the factors that affect the CFA pile productivity and cost. A productivity index (PI) is developed to quantify the effect of subjective factors on the CFA process productivity. Current research concludes a PI value of 0.78 out of 1.0 (efficiency). Several models are designated to assess the CFA pile's cycle time, productivity, and cost using deterministic approach. Various charts are developed to show this assessment based upon these models. Results show that the cycle time for 12.19 m depth and (0.36 m) (14 in) diameter piles is 16 min; however, its productivity is 24 piles (holes)/day. The developed tools play an essential role in the CFA decision making process. This paper is relevant to both researchers and practitioners. It provides charts for practitioners' usage to schedule and price out the CFA pile construction projects. In addition, it provides the researchers with a methodology of applying the deterministic approach to the CFA pile construction process and its limitations.