Flexural Performance and Feasibility Study of Cold-Formed Thin-Walled Steel-Reed Board Composite Beams

Abstract

To explore the application potential of green and renewable materials in structural engineering, this paper proposes a novel composite I-beam composed of cold-formed thin-walled steel and reed board. Through a combined approach of theoretical analysis and experimental investigation, the flexural performance, failure mechanisms, and sensitivity of key design parameters of this composite beam are systematically studied. The results indicate that reed board and cold-formed thin-walled steel exhibit good mechanical compatibility. Effective composite action can be achieved through reliable interfacial connections, significantly enhancing the flexural stiffness and load-carrying capacity of the member. The observed failure modes in the tests were primarily characterized by crushing or tensile fracture of the reed board, supplemented by interfacial bond failure, with the failure process demonstrating a certain degree of ductility. Parametric analysis reveals that the steel thickness, reed board thickness, and interfacial connection method significantly influence the ultimate load capacity and deformation behavior of the beam. A simplified load-carrying capacity calculation model, established based on the plane-section assumption and material constitutive relationships, shows good agreement with the experimental results, with an average error within 15%, validating the model's rationality. This study preliminarily demonstrates the technical feasibility of cold-formed thin-walled steel-reed board composite beams, providing a theoretical basis and experimental reference for the engineering application of plant fiber-based composite materials in light steel structural systems.