The project discussed in this paper is a tower located in Bucharest with a height of 137 m. To find the optimal layout of the foundation elements with respect to minimising vertical displacements, conventional calculations are in general not sufficient and advanced numerical modelling of the soil-structure interaction is essential. The paper shows results from numerical analyses with the objective to assess the settlement behaviour of the tower. Due to the geometric layout 2D analyses proved to be too conservative and therefore a number of 3D analyses have been performed. Different arrangements of diaphragm wall panels have been investigated to find an economical and technical feasible solution for the layout of the foundation elements. For the executed deep foundation concept a parametric study based on soil data recently published in the literature is presented. Finally results from 3D finite element simulations of an in situ load test, performed to obtain additional information of the settlement behaviour of the deep foundation, are presented. The test was conducted on a diaphragm wall element (barrette) using the “Osterberg Method”.