A study on fundamental frequency of cold-formed thin-walled steel-gypsum based self-leveling mortar composite floor

Two full scale models of cold-formed thin-walled steel-gypsum based self-leveling mortar composite floor were carried out for vibration test under four dynamic loadings which included walking along and transverse to the floor joist, walking along the diagonal direction of floor and hammer impact. The effects to the natural frequency of composite floors were studied when steel mesh was installed. The study showed that the natural frequency of composite floor did not change greatly with the change of external excitation. It did not significantly increase the natural frequency of composite floor via installing steel mesh into the gypsum based self-leveling mortar. The ABAQUS finite element software was used to conduct modal analysis of test models as well as variable parameter analysis based on the calibrated model. The research shows that fundamental frequency of cold-formed thin-walled steel composite floor can be improved by increasing plate thickness of floor joist and reducing floor span. The change of floor slab thickness and floor width along with strengthening flat strap and blocking brings little effect to the fundamental frequency of cold-formed thin-walled steel composite floor. Based on parameter analysis, composite floor can be equivalent to a simply supported beam with uniform quality and stiffness for computing the fundamental frequency of cold-formed thin-walled steel composite floor. © 2018, Editorial Office of Journal of Vibration and Shock. All right reserved.