Prediction of the bearing capacity of piles based exclusively on N values of the SPT
Luciano Décourt
Abstract
Quaresma, in which the author's experience in estimating the bearing capacity of piles based solely on data from Standard Penetration Tests was confronted with data from load tests, most of them belonging to Ing. Interest has, then, arisen towards investigating the validity of the method originally developed by the author for traditional piles, i.e. precast concrete piles, Franki piles etc, as applied to piles of high bearing capacity, especially those going through soil with high N values. The ultimate bearing capacity derived from skin friction along the shaft shall than be determined by using the afore mentioned expression: where N values smaller than 3 must be taken as 3 and N values greater than 50 must be taken as 50 for the reasons exposed before. In the present case, the point bearing capacity is not taken into account, due to the fact that settlements of several centimeters are required for its mobilization.