Comparison of Deep Foundation Systems using 3D Finite Element Analysis Employing Different Modeling Techniques

Finite element analyses for the deep foundation of the Donau City Towers in Vienna are discussed in this paper. The towers are located very close to each other, thus interaction of the two towers has to be taken into account for the design of the foundation system. The objective of the analysis was twofold, namely to calculate maximum and differential settlements to be expected and optimisation of the layout of the foundation elements. In addition to the foundation concept actually constructed alternative solutions have been studied in a numerical study and the results of this study are presented in this paper. Different techniques for modelling the foundation elements in the numerical model, namely a standard approach using volume elements and the embedded pile concept, are investigated. The latter approach is discussed is some detail before the case study is presented.