| Cold-formed composite floor is new formed by C-section cold-formed joists on which are profiled steel sheets and self-leveling mortar(or fine aggregate concrete). This paper mainly describes the results of bending bearing capacity by tests and finite analysis and the simplified method is proposed.Two full scale test specimens were tested which were difference by concrete slabs. One was self-leveling mortar. Another was fine aggregate concrete. The design, the assembly, the material property, the trial device, measuring points, the loading system, the experimental phenomena and the analysis of the test data are introduced in details. The results show that the bearing capacity of the two specimens are almost same, while the rigidity of the self-leveling mortar composite floor is smaller.ANSYS finite analysis involving materials nonlinear and geometric large deformation is used to simulate the test specimens under the vertical load. Members of the steel are SHELL181 elements while SOLID65 element for concrete slabs and BEAM188 elements for screws between the profiled steel sheets and the joists. Comparing the results of the tests and finite analysis shows that the finite models are accurate by the difference within 5% of the test. The ratio of effect of the span-depth and the ratio of height to thickness of the web are studied showing that with the ratio of height to thickness of the web increasing, the elastic stiffness, the bearing capacity decrease. The smaller of the ratio of effect of the span-depth, the higher of the capacity of the composite floor; The smaller of the distance of the screws, the the higher of the capacity of the composite floor; the higher of the steel strength, the the higher of the capacity of the composite floor; the thickness of the concrete is not very important.Based on the test and the nonlinear finite element analysis, the simple corresponding design method of the composite floor is proposed. Compared with experimental data and ANSYS results, the simple method has high degree of accuracy. |
