FEM simulation of vibrations in building: from volume to shell elements

The problem of vibrations in buildings situated in the proximity of railway tracks is a major concern for the resident's comfort. More and more studies focus on this problem using FEM models, with shell elements for the building's walls and floors. However, the validity of this simplification is never fully justified, and it raises questions concerning the dimensions to apply to the model. The model of a building made of 3D elastic elements is compared to its simplified version made of shell elements. Three geometries with different dimensions are tested to find the one closer to the reference model. Different shell offsets are also tested. The results show great differences of floor vibration levels, mostly for high frequencies, depending on the dimensions of the geometry and the offset. The shell configuration with the closest results to the reference model is discussed.