Damping systems are designed to stabilize the structures by concerning any types of external excitations that can occur. Decreasing the structural movements is extremely important for structures to preserve their integrity. Passive Tuned Liquid Column Dampers -TLCD- are preferred systems in practice due to their simple structures and not requiring an external energy input and therefore, they can be effectively used in the suppression of structural oscillations. In this thesis, the damping performance of a TLCD was studied, specifically considering the effect of the head loss coefficient on the performance of a liquid column. An analytical model was produced, and the equation of motions was solved in 1D. Experiments were performed to confirm the analytical solutions and to gain information where the analytical model was not sufficient in the case of two orifices that were close to each other. An experimental design was used to obtain the head loss value of the tuned liquid column damper. A series of experiments were completed to observe the effect of the head loss coefficient on the damping performance of the tuned liquid column dampers. According to experimental and analytical results, a relation between the damping ratio of the system and the head loss coefficient of the damper was noted. It was experimentally monitored that there is an optimum spacing between two orifices where the performance of the TLCD may be maximized. It was also noted that, according to experiments damping ratio of the system was improved by 10.5%.