Discussion of “Effects of Relative Density on the Measured Response of Piles under Combined Uplift and Lateral Loading”

The authors have done a judicious study involving rigorous physical testing to predict the behavior of piles in combined uplift and lateral forces by varying the length (length/depth ratio, L=D) of a pile and the relative density (RD) of a sand layer surrounding the pile.The authors' findings indicate that the increase in capacities is higher for shorter piles embedded in loose to medium-dense soils than the longer piles and for dense soil.The authors attributed this increase in pile capacity in the lateral load case to initially mobilized resistance on piles subjected to initial loading, and in the uplift load case to unsymmetrical curved surface failure theory.However, increase in pile capacities also accompanies the increase in deflections and displacement, which could compromise the stability of prototype models.Although pile deflection is measured in the study, key parameters such as depth of fixity and effective pile length are overlooked.Consequently, the discussers wish to highlight several factors and observations that warrant attention from fellow researchers, as outlined in the following.