The objective of this thesis is the investigation of the transmission of vibrational power between beam-like and plate-like structures with joints using Statistical Energy Analysis (SEA) and an experimental approach. In the case of the L-shaped plate the influence of different structure parameters is investigated to determine possible ways to reduce both the transmitted power and the noise radiated by the receiver structure. The total transmitted power is measured and compared to theoretical predictions. Also power maps are generated which show the transmission of vibrational power from the source beam to the receiver beam. In the power flow measurements three different techniques are implemented with similar results which all match the analytical results.