A parametric study of different analytical design methods to determine the axial bearing capacity of monopiles

In Europe many offshore wind power parks have already been realized and more are planned. Often monopiles are used as foundation for wind power plants. The determination of the axial pile capacity of monopiles is among the important issues for offshore energy projects. Despite progress made so far in this field, there are still big challenges faced by researchers. Among them is to provide guidance to assist engineers in the selection of an appropriate design method for the soil condition and pile configuration of interest. First, different state of the art methods (API, Fugro-05, ICP-05, NGI-05 and UWA-05) together with two new methods (HKU-12 and a German approach) to determine the axial bearing capacity based on the cone resistance of the soil are presented. Afterwards there is a summary of different approaches to determine the average cone resistance value. Furthermore a sensitivity analysis is carried out to show the influence of the pile diameter and the cone resistance on the predicted axial bearing capacity of the different design methods. In the last part, published field tests are used to compare the presented design methods and to identify their potential for reliable predictions for engineering practice. In addition to existing publications, these comparisons contain the two new design methods to determine the axial bearing capacity.