A simplified model for the design of floor structures with vibrating sources for architectural applications

Abstract: When designing a building, sound is one of the problems to take into account. Vibrating machines, such as ventilation fans, water pumps and compressors, generate structure-borne sound. The structure-borne sound travels up the structure of the building and generates sound in adjacent rooms. To be able to predict the sound radiated in the adjacent rooms when designing a building, a semi-analytical model has been developed. Using the incident vibrations from the floor plate where the vibrating machine is standing, the transmission loss in the junction between the floor plates and the wall plate is calculated. This can bed one in every junction in the building, creating a system of multiple junctions. The sound radiation to the adjacent rooms is later approximated using the velocity of the plates.The model is verified with measurements in two case studies. This shows that the model has good potential in predicting the normal acceleration amplitudes in the relevant plates. The two case studies have different geometric properties and different sources. The comparison between the model and the measurement gives similar results. The model analyses the output of the bending waves since this is the wave type that radiates sound, but longitudinal waves are present in the model. With only two case studies it is too early to say that the model works for all systems, but it could be used as a fist approach. The model, right now, is restricted to isotropic, homogeneous material without losses. A parametric study shows that the transmission loss is dependent on the ratio between the thicknesses of the floor plate and the wall plate. The ratio should be as large as possible to get a high transmission loss, but depends on how the junction is structured.