Study on in-plane and out-of-plane bearing capacity of cold-formed steel composite floor with opening

In this study, the in-plane cyclic and out-of-plane flexural performances of cold-formed steel (CFS) floors were experimentally investigated. The experimental study provided significant test data for theoretical analysis. Subsequently, the in-plane and out-of-plane performances were modeled using ABAQUS software. The numerical results agreed well with the test results. Consequently, finite element models of the CFS floors with openings were constructed. The effects of opening size, opening reinforcement measures, screw spacing, opening eccentricity, and slab material on the bearing capacity of CFS floors with openings were examined. According to the findings, the measures for improving the bearing capacity of the floor with opening include reducing the opening size, incorporating opening reinforcement measures, minimizing the screw spacing around the opening, keeping the opening centered, and prioritizing a steel deck and GSU (con-crete) combination for the composite slab. In addition, the main parameter affecting the in-plane bearing capacity of the floor with opening was the opening size, and the main parameters affecting the out-of-plane bearing capacity of the floor with opening were the opening size and the opening eccentricity. Based on that, combining the simplified model of wide flange deep beam and T-shaped composite beam, the calculation method for evaluating the in-plane and out-of-plane ultimate bearing capacities of CFS floors with openings were developed by data fitting of the key factors. The calculated results were agreed well with the FE results. This study provides a scientific basis for the design of composite floors for multistory CFS structures.