Evaluation of Negative Skin Friction on Precast Piles 

Federal University of Juiz de Fora, Brazil

Abstract: This study aims to better understand negative skin friction. The phenomenon is conceptualized, some situations in which it takes place are presented as well as some factors that contribute to the nature, magnitude and ways to minimize it. The main forecasting methods in the literature review are discussed. Estimation of negative skin friction is performed for a hypothetical situation on driven single piles or pile groups (when it is feasible through the methodology) embedded within a soil profile made up of soft to very soft organic clay layer, which is superposed on a compact sand layer. Underlying this sand layer there is a residual soil. It is considered a 3 meter deep embankment. The type of pile is precast concrete piles with a closed end. For the pile group it is considered six precast piles connected to a pile cap. The values of the estimated negative skin friction ranged from 68 to 497 kN. Significant differences were expected using several methods, since they are developed based on different considerations. It was noted the relevance of studies on instrumentation regarding this field, particularly in Brazil, where there is a lack of studies on the subject.