The main aspect of this master thesis is the experimental and numerical investigation of the clamping in the WAAM process. Wire + Arc Additive Manufacturing (WAAM) is a wire- and arc-based additive manufacturing process in which the component to be manufactured is generated layer by layer using a modified build-up welding process. Based on a literature search carried out at the beginning regarding important topics concerning this master thesis, a comprehensive numerical parameter study follows, which deals with the thermomechanical structure simulation itself as well as with a numerical analysis of the clamping conditions at the WAAM process. This was created with the FE-program Simufact-Welding. The main parameters which were varied in this study are the thermomechanical decoupling degree, the mesh fineness used, the screw modelling and the clamping sequence of the clamping elements as well as the clamping configuration used. In the experimental part of this work, a parameter determination concerning the WAAM process for the material Ti-6Al-4V was carried out at the beginning. Based on this, a normal as well as a pendulum bar were then set up on a base plate using WAAM. The temperature curves at selected points were recorded using thermocouples and the temperature fields of the corresponding numerical models were calibrated. Subsequently, welding tests were carried out in which, in addition to the temperature profiles, the profiles of the bolt forces in the clamps as well as the strains on the base plate surface and the distortion of the base plates were determined. This work is concluded by the following comparison between the experimental values and the corresponding numerically calculated ones. The results of this work clearly show that both the force curves of the clamping and the stress curves on the base plate surface can be qualitatively well estimated with the aid of a numerical simulation, whereby significant differences between the numerically and experimentally determined values were evaluated.