ABSTRACT
This chapter includes the contributions that testify the vivid technological development taking place in the soil displacement screw pile market. It identifies the need for a rigorous definition of the uncertainties that are covered by each of the partial factors of safety and of the design parameters to be used in a particular approach. Researchers should also develop tools to better quantify the adequacy of a site to serve as a calibration frame work for pile capacity, the number of tests required to assess installation factors, and dwell on the validity of the traditional separation between friction and end bearing. The trend that is now emerging consists in decreasing the factor of safety against friction, fueled by the realization that its evaluation over a given site is less variable than that of the end bearing. That lower variability of the friction relative to that of the end bearing finds a logical explanation in the magnitude of the depth range.
