• A novel concrete-cold-formed steel-OSB composite floor system is proposed. • Analyzed the effects of parameters, such as the placement of C-shaped steel and the arrangement of the steel mesh, on bending stiffness, load-bearing capacity, and deflection. • Proposed a stiffness reduction method to assess the impact of interface slip on bending stiffness and mid-span deflection. • Developed a predictive formula for the bending load-bearing capacity of the new composite slabs. To address the inherent limitations of insufficient stiffness and load-carrying capacity in traditional lightweight floor slabs, this study innovatively proposes a cast-in-place cold-formed steel (CFS)-oriented strand board (OSB)-concrete composite system. The proposed system consists of concrete with embedded C-sections and a bottom OSB panel. Reinforcing bars are incorporated into the concrete to control cracking and enhance durability. Six full-scale specimens, each with distinct configurations, were subjected to flexural loading to systematically investigate the influence of C-section orientation (vertical versus horizontal web), reinforcement layout, and the presence of extruded polystyrene (XPS) infill on structural performance. Test results indicate that the bond between the concrete and C-sections is strong, with no observable slip. Compared with vertical placement, horizontal placement of C-sections significantly improves both flexural stiffness and ultimate load capacity. The inclusion of reinforcement effectively reduces cracking and enhances overall performance. Although the XPS infill slightly reduces cracking and yielding loads, it substantially decreases the slab's self-weight with minimal impact on its ultimate capacity. Additionally, an equivalent stiffness method was employed to theoretically analyze the flexural stiffness of the composite slabs. Predictive formulas for flexural capacity under different structural configurations were established. The theoretical predictions closely matched the experimental results, establishing a robust and reliable foundation for the design and practical engineering application of this novel composite floor system.
Duan et al. (Sun,) studied this question.