Modal analysis for floors in lightweight buildings

High rise buildings built with wooden framing systems is of major interest for several reasons. It is said to be environmental friendly material, the production cost might be lower and the weight of the house is very low. The development of wooden housing is faster than the development of acoustical prediction methods for those houses. The calculation standard EN 12354 is under evaluation since it cannot include most of the wooden houses that are built. It is important during such a work to have a great understanding of the acoustical behaviour for the wooden houses. The floors in lightweight constructions usually consist of plates that are stiffened by beams and by the dividing walls. In this study the wave equation for a plate is expanded by Fourier series and an analytical solution in terms of the eigenmodes of the entire system is presented. The studied system consists of one lightweigt floor that is simply supported at its boundaries. Preliminary results show that the vibration level is directed by the presence of the beams.