A comparison of friction piles bearing capacity based on theoretical and empirical mathematical models.

Abstract

One can find in literature lots of different models to predict axial capacity of piles .This study has been carried out to compare some selected empirical (semi-empirical) and theoretical models used in Norway or internationally. The comparisons were made among the various models with respect to the static load test result, which is widely believed to be providing a reliable pile capacity. The study has been undergone based on the data obtained in the bridge project over the Drammen Selva river in the city of Drammen in Norway. In this study, I have included four calculation models, namely the Janbu theoretical models (derived based on plasticity theories and earth pressure approach), the Norwegian Pile Guideline (peleveiledningen (2005)), API RP 2A LRFD (2007), NGI-99 methods. The Norwegian Pile Guideline (2005) is sort of mixed empirical and theoretical approach. The last two are purely empirical. Recent literature on set up effect were also included in this study and the increase in capacity with time was also accessed in both using a prediction model and static load test result which was performed in various time intervals. Additionally, a back calculation of parameters was also performed in the study based on the static load test results, for a possible use in design of neighboring piles showing similar soil type and soil parameters. We should be aware that the findings of this study is considered to be of limited nature and should not be generalized.