Flexural performance of steel beam wrapped with polyvinyl alcohol‐basalt fiber ceramsite concrete: Experimental, numerical analysis, and calculation

Abstract

Steel structures possess excellent mechanical properties but poor fire resistance. To address the insufficient fire resistance of steel structures, this study proposes a novel wrapped material composed of polyvinyl alcohol, basalt fiber, and ceramsite concrete (PVA‐BF CC). The fire resistance of this novel concrete was investigated via one‐face fire exposure test, which showed that a 50 mm‐thick PVA‐BF CC layer maintained the unexposed surface temperature below 400°C even after 2 h of heating. The flexural performance of the steel beam wrapped with PVA‐BF CC was further investigated via full‐scale bending experiments and finite element simulations. The investigated parameters included the reinforcement method (steel wire mesh (SWM) and reinforced bars) and the ratio of steel wire mesh. The wrapped steel beams exhibited excellent flexural performance in terms of yield and peak loads. SWM‐reinforced beams outperformed those with conventional bars in both load capacity and ductility. For beams wrapped with PVA‐BF CC and steel wire mesh, increasing the wire diameter enhanced the yield and peak loads but slightly reduced ductility. By contrast, increasing the mesh spacing improved ductility but led to a gradual decrease in the loads. Finally, design recommendations and a calculation method for the flexural capacity of the steel beam wrapped with PVA‐BF CC are proposed to support practical engineering applications.