Woodsol is a Norwegian research project aiming at developing a timber building construction system based on long span floor elements and moment resisting frames. Due to the long span requirement and the lightweight construction, we expect major challenges at low frequencies when looking at the impact sound insulation. To address this issue and develop suitable strategies for improvement, we studied among other the modal properties of the floor element. We scheduled a large measurement program allowing for investigating different floor sizes, the effect of additional mass in the floor cavity and two type of boundary conditions. The first type are free-free boundary conditions aimed at collecting data for the validation of the finite element models. As the other boundary conditions type, we built one cell of the building frame system accurately representing the mounting situation of the floor element on the moment resisting frame with the special connectors. On each setup, we performed an experimental modal analysis of the floor elements, using the roving hammer technique with multiple reference accelerometers. The paper will present the results obtained so far and discuss both the measurement procedure and analysis of the measurement data. We will also discuss the expected effect of the modal behavior on the impact sound insulation of the floor elements.
