This master's thesis is dealing with the numerical simulation of tuned liquid column dampers (TLCD), which are used to reduce the resonance amplitude of vertically oscillating bridge structures. The functionality of these dampers is based on the movement of a liquid mass in a sealed tube, induced by the structural oscillation. The damping is achieved by the two motions being phase delayed to each other.<br />The first chapters are focused on the theoretical background of vibration dynamics and the TLCD. Afterwards the performed vibration experiments on a steel structure model of a bridge are described and their results are analysed. The major part of this thesis is dedicated to numerical simulations. The development of the used finite element model and the realisation of realistic vibration behaviour in the simplified small - scale model are explained. Based on this model, parameter studies are performed to analyse the influence of certain TLCD - characteristics on the amount of damping. Dampers with different resonance frequencies and varying geometries are tested and the different structural displacements of the model are compared. The results of these studies confirm the importance of an exact adaption of the damper to the characteristics of the main structure, but as the numerical simulation shows only an approximation of the real behaviour of the fluid motion in the damper, it cannot completely replace experimental studies on real structures yet. Anyway it is very helpful to analyse certain system variations which would be difficult to accomplish on a real model.