Axial compressive capacity of driven piles in sand: a method including post-driving residual stresses

In this paper, empirical formulae were developed between the well-known pil e bearing capacity factors (N-q and beta) and parameters which include fric tion angle of sand, relative density, average effective vertical stress, an d deformability of the soil below the pile toe. The developed empirical for mulae were totally based on a database comprised of 28 well-documented comp ressive pile load tests collected exclusively from geotechnical literature. The actual measurements of shaft and end-bearing resistances of each pile in the database were adjusted to account for post-driving residual loads. C alculation of pile bearing capacity factors (N-q and beta) was based on the adjusted shaft and end-bearing resistances rather than the actual unadjust ed measured resistances for residual loads. Comparison of predicted and mea sured compressive capacity of an independent database comprised of 18 pile load tests showed that the developed formulae yield a reasonably accurate e stimate of compressive pile capacity in cohesionless soils.