New approaches for floor vibrations of steel–polymer–steel sandwich floor systems

Diverse sandwich floor systems have recently been developed owing to their significant features, such as high strength and low weight. Because sandwich floor systems generally have a high bond strength between the face and core materials, they exhibit fully composite behaviors under large deformations. The main feature of sandwich floor systems is that face materials primarily resist bending moments, whereas core materials resist shear forces under flexural loading. Thus, the flexural behavior of the sandwich floor systems should consider shear deformations owing to relatively weak and soft core materials compared with face materials. However, current publications, such as guides and recommendations, for evaluating or designing floor vibration propose estimation equations derived from a uniform section beam, commonly known as the Euler–Bernoulli beam theory, which is governed by pure bending behavior. This approach should be developed when evaluating or designing floor vibrations of sandwich floor systems, which simultaneously exhibit bending and shear behavior under flexural loading. Therefore, this paper proposes new approaches, which include shear and bending deformations, for the floor vibration performance of the sandwich floor system, particularly the steel–polymer–steel sandwich floor system. New approaches are derived from the sandwich beam theory and deformation-based approach with a single-degree-of-freedom model; they were validated through a comparison with laboratory-scale and full-scale tests in an actual building. For full-scale tests in an actual building, the two conditions, with and without finishings, were considered to conduct the floor vibration tests. Furthermore, a more efficient and simple approach derived from the deformation-based approach is highly recommended for practical design.